Unit 8; 1st Grade; Foundation of Numbers up to 99
5E Lesson Plan Math
Grade Level: 1st
Subject Area: Math
Lesson Title: Unit 8 Foundations of
Lesson Length: 10 Days
Numbers up to 120
THE TEACHING PROCESS
Lesson Overview
This unit bundles student expectations that address the understanding of whole
numbers up to 120, comparing numbers using place value, and ordering these
numbers using an open number line. According to the Texas Education Agency,
mathematical process standards including application, tools and techniques,
communication, representations, relationships, and justifications should be
integrated (when applicable) with content knowledge and skills so that students
are prepared to use mathematics in everyday life, society, and the workplace.
Prior to this unit, in Unit 06, students explored base-10 place value system as they
explored whole numbers up to 99. Students composed and decomposed numbers
through 99 using concrete objects, pictorial models, and numerical
representations. In addition, students used place value relationships and tools,
such as a hundreds chart, as they generated numbers more or less than a given
number. Students compared whole numbers up to 99 using comparison symbols
and were introduced to using place value and open number lines to order whole
numbers.
During this unit, students extend their understanding of the base-10 place value
system to include the hundreds place as they continue exploring the foundations
of whole numbers up to 120. Students compose and decompose numbers through
120 as a sum of so many hundreds, so many tens, and so many ones using
concrete objects (e.g., proportional objects such as base-10 blocks, nonproportional objects such as place value disks, etc.), pictorial models (e.g., base10 representations with place value charts, place value disk representations with
place value charts, etc.), and numerical representations (e.g., expanded form and
standard form). Students use place value relationships to generate numbers that
are more or less than a given number using tools (e.g., a hundreds chart,
calendar, base-10 blocks, etc.). Students use place value to compare whole
numbers up to 120 and represent the comparison using comparison language and
comparison symbols. Students also extend using place value and open number
lines to order whole numbers up to 120.
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Unit Objectives:
Students will… extend their understanding of the base-10 place value system to
include the hundreds place as they continue exploring the foundations of whole
numbers up to 120. Students compose and decompose numbers through 120 as a
sum of so many hundreds, so many tens, and so many ones using concrete
objects (e.g., proportional objects such as base-10 blocks, non-proportional
objects such as place value disks, etc.), pictorial models (e.g., base-10
representations with place value charts, place value disk representations with
place value charts, etc.), and numerical representations (e.g., expanded form and
standard form). Students use place value relationships to generate numbers that
are more or less than a given number using tools (e.g., a hundreds chart,
calendar, base-10 blocks, etc.). Students use place value to compare whole
numbers up to 120 and represent the comparison using comparison language and
comparison symbols. Students also extend using place value and open number
lines to order whole numbers up to 120.
Standards addressed:
TEKS:
1.1A: Apply mathematics to problems arising in everyday life, society, and the
workplace.
1.1C: Select tools, including real objects, manipulatives, paper and pencil, and
technology as appropriate, and techniques, including mental math, estimation, and
number sense as appropriate, to solve problems.
1.1D: Communicate mathematical ideas, reasoning, and their implications using
multiple representations, including symbols, diagrams, graphs, and language as
appropriate.
1.1E: Create and use representations to organize, record, and communicate
mathematical ideas.
1.1F: Analyze mathematical relationships to connect and communicate
mathematical ideas.
1.1G: Display, explain, and justify mathematical ideas and arguments using
precise mathematical language in written or oral communication.
1.2B: Use concrete and pictorial models to compose and decompose numbers up
to 120 in more than one way as so many hundreds, so many tens, and so many
ones.
1.2C: Use objects, pictures, and expanded and standard forms to represent
numbers up to 120.
1.2D: Generate a number that is greater than or less than a given whole number
up to 120.
1.2E: Use place value to compare whole numbers up to 120 using comparative
language.
1.2F: Order whole numbers up to 120 using place value and open number lines.
1.2G: Represent the comparison of two numbers to 100 using the symbols >, <, or
=.
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Unit 8; 1st Grade; Foundation of Numbers up to 99
ELPS:
1A use prior knowledge and experiences to understand meanings in English;
2D monitor understanding of spoken language during classroom instruction and
interactions and seek clarification as needed;
3A practice producing sounds of newly acquired vocabulary such as long and
short vowels, silent letters, and consonant clusters to pronounce English words in
a manner that is increasingly comprehensible;
3D speak using grade-level content area vocabulary in context to internalize new
English words and build academic language proficiency;
3H narrate, describe, and explain with increasing specificity and detail as more
English is acquired;
Misconceptions:
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Some students may think the digit 1 in the number 120 represents the value
1 instead of the value 100 ones, 10 groups of 10, or 1 group of 100.
Some students may think the decomposition of 115 is 1 + 1 + 5 instead of
100 + 10 + 5, not realizing the importance of the place value in the
expanded representation.
Some students may think a number can only be decomposed one way,
when the number can actually be decomposed multiple ways (e.g., one
hundred six could be represented as 10 groups of 10 and 6 ones, 106 ones,
8 groups of 10 and 26 ones, etc.).
Some students may think the total value of a number changes when the
number is represented using different decompositions, not realizing that the
sum of the addends in each decomposition remains the same.
Some students may think, when comparing numbers, a number value is
only dependent on the largest digit, regardless of the place value location
within the number (e.g., when comparing 89 and 112, the student may think
that 89 is larger because the digits 8 and 9 are larger than any of the digits
in the number 112).
Some students may think numbers are always ordered from smallest to
largest rather than understanding that quantifying descriptors determine the
order of numbers as they are read from left to right (e.g., largest to smallest,
smallest to largest, etc.).
Some students may think all number lines or open number lines must begin
with zero rather than being able to visualize a number line or open number
line that displays an isolated portion of a number line or open number line.
Some students may think the less than and greater than comparison
symbols are interchangeable rather than understanding the meaning of
each symbol and how to appropriately read and write each symbol.
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Underdeveloped Concepts:
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Some students may still be in the one-to–one correspondence counting
stage making it difficult to use the base-10 blocks or other manipulatives
used for representing 10s.
Vocabulary:
Compare numbers – to consider the value of two numbers to determine
which number is greater or less or if the numbers are equal in value
Compose numbers – to combine parts or smaller values to form a number
Counting (natural) numbers – the set of positive numbers that begins at
one and increases by increments of one each time {1, 2, 3, ..., n}
Decompose numbers – to break a number into parts or smaller values
Digit – any numeral from 0 – 9
Expanded form – the representation of a number as a sum of place values
(e.g., 119 as 100 + 10 + 9)
Numeral – a symbol used to name a number
Open number line – an empty number line where tick marks are added to
represent landmarks of numbers, often indicated with arcs above the
number line (referred to as jumps) demonstrating approximate proportional
distances
Order numbers – to arrange a set of numbers based on their numerical
value
Period – a three-digit grouping of whole numbers where each grouping is
composed of a ones place, a tens place, and a hundreds place, and each
grouping is separated by a comma
Place value – the value of a digit as determined by its location in a number
such as ones, tens, hundreds, etc.
Standard form – the representation of a number using digits (e.g., 118)
Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2,
3, ..., n}
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Related Vocabulary:
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Base-10 place
value system
Comparative
language
Comparison
symbols
Decrease
Equal to (=)
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Greater than (>)
Hundreds place
Increase
Landmark (or
anchor) numbers
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Less than (<)
Magnitude
(relative size)
Ones place
Tens place
Unit 8; 1st Grade; Foundation of Numbers up to 99
List of Materials:
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More or Less, by Stuart J. Murphy or similar text
120 chart (RS1)
Counters
Place Value Disks (18 disks of 1, 10 disks of 10 and 1 disk of 100 per pair;
(RS2)
0-9 Spinner for each pair of students (RS3)
Place Value Mat (RS4)
0-99 Chart (RS5)
Close, Far and In Between resource sheet (RS6)
A set of four cards with three numerals on each (the numerals should be
from the same row or column found on the 0-120 chart)
Tape or glue
2 different colored counters
Spinner labeled 1 more, 1 less, 10 more, 10 less (RS7)
Spinner labeled with 10 and 1 (RS8)
Number Hotel game board (RS9)
Arrow cards (RS10)
Counters to use on the game board
Base 10 blocks
10 frames (RS11)
Folder (to hide riddle)
Student dry erase boards or paper and pencil
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Unit 8; 1st Grade; Foundation of Numbers up to 99
INSTRUCTIONAL SEQUENCE
Phase One: Engage the Student
Background:
This activity is centered on number relationships and counting. Students need to
expand their basic ideas of place value understanding which include base-ten
grouping, oral names, and written names, to relative magnitude. Students should
be able to relate a number’s relationship to another number as: much larger, much
smaller, close to, or about the same.
Day 1 Activity:
Materials:
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More or Less, by Stuart J. Murphy or similar text
0-120 chart
Counters
Part I
Gather students in a common area and read More or Less, by Stuart Murphy, or a
similar book. During the story, chart the guesses the students gave and identify
them on the 120 chart. Then, have a class discussion about how the children
guessed the principal’s age. Play the same type of game by having students
guess your principal’s age. Students will begin guessing the principal’s age; once
the number is given, have the students locate it on the 120 chart. Only give the
student’s clues by telling them that the number is more or less.
Part II
Partner the students to play a version of More or Less. Player One will write a
number on a sticky note and cover it. Player Two will then try to guess the covered
number as Player One guides them to an answer by saying, more or less. Every
number that is guessed is then covered on the 120 chart with a counter. Once the
number is revealed or correctly guessed, the players switch roles and play again.
Guiding Questions:
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What was the number? (answers may vary)
How many guesses did you need to find the number? (answers may vary)
Was the number more of less than what you thought? (answers may vary)
What was the hardest number to guess? Why? (answers may vary)
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Unit 8; 1st Grade; Foundation of Numbers up to 99
What’s the teacher doing?
What are the students doing?
Read More or Less, by Stuart J.
Murphy or similar text
Listen to book
Chart “guesses” on the 120 chart
Discuss how the children, in the book,
guessed the principal’s age
Lead class discussion
Guess their principal’s age
Facilitate a game of guessing where
students guess their principals age
Play “More of Less”
Facilitate game as pairs of students
play “More or Less”
Answer guiding questions
Ask guiding questions
Phase Two: Explore the Concept
Background:
Students should have experience working with numbers up to 100 in previous
tasks. Students should be able to build numbers with an understanding of place
value. This task is focused on students counting collections of objects and using
their understanding of place value to record larger amounts. The discussion about
what happens when a student reaches ten groups of ten should happen during the
modeling of this game. Students should be aware of how this number is different,
what happens to the digits and understand when a new place value position is
needed. This is not intended to introduce the strategy of regrouping.
Day 2 Activity:
Materials:
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Place Value Disks (18 disks of 1, 10 disks of 10 and 1 disk of 100 per pair)
0-9 Spinner for each pair of students
Place Value Mat
0-99 Chart
The teacher will model the “Make A Trade” game with the class. The modeling of
this game is important to lead to the discussion about what happens when a
student reaches ten disks of ten. The students should understand that when there
are ten groups of 10 a new place is created. Model this idea and ask students
about the why this number is different. The understanding of the 3 digits should be
modeled for students to gain a deep understanding of what is happening. Students
should discuss how this number differs, what happens to the digits and understand
when a new place value position is needed. This is not intended to introduce
the strategy of regrouping.
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Students work with a partner and play the “Making A Trade” game. Students take
turns spinning the 0-9 spinner and creating a number sentence with the two
numbers. Students will find the sum and add this number of cubes to the place
value mat. Once the ones column is full the student will exchange the 10 disks of
one for a 10 disk and place it in the tens column. Players will work together on one
mat until they have 10 disks of 10. Allow students to play without any recording
and focus on building the representation.
What’s the teacher doing?
What are the students doing?
Model “Building Towers of 10” game
Playing “Building Towers of 10” game
with a partner.
Circulate to make sure students
understand the concept of building
numbers larger than 99.
Phase Two: Explore the Concept
Day 3 Activity:
Materials:
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Place Value Disks (18 disks of 1, 10 disks of 10 and 1 disk of 100 per pair)
0-9 Spinner for each pair of students
Place Value Mat
0-99 Chart
Students work with a new partner and play the “Make A Trade” game again. This
time, the students will record their equations and keep up with the total sum on a
0-99 chart. Students will take turns spinning the 0-9 spinner and creating a number
sentence with the two numbers. For instance, if the first two numbers are 7 and 2,
the student will record 7 plus 2 equals 9 on the recording sheet. Then, the players
collect that many 1 disks and adds them to the place value mat. Students will use
one place value mat to manipulate the number. After each spin, the player must
tell the number sentence created, and the total number of objects counting by 10s
and 1s. Recording the equation allows additional practice with writing addition
equations correctly. Students will then use a cube or counter to count the total
number of objects on a 0-99 chart. If the current number is 16 and a player spins a
2 and 4, then the player will record the equation and then add 6 + 16 on the place
value mat and the 0-99 chart. This will allow them to check the representation with
the total number on the 0-99 chart after each turn. Both players are adding the
disks to one mat and the 0-99 chart to form a running total. Together partners
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Unit 8; 1st Grade; Foundation of Numbers up to 99
determine their new total until they have reached 100. Discuss what happens to
this number. Is there another chart that could be created for numbers larger
than 99? (yes, a 120 chart) Partners continue rolling and collecting objects until
they create a collection of 100. The teacher should walk around and monitor
students while playing this game. Ask the students questions throughout the game
to ensure understanding.
A follow up class discussion is very important to build deeper understanding. Ask
questions throughout the game and revisit the same questions during the class
discussion. How many equations did it take you and your partner to get to
99? (Answers will vary) How does the disk representation help us find the
number on the 99 chart? (We look at the number of 10’s and find that row on
the chart) Discuss how the tens place digit determines the decade where the
number can be located.
Guiding Questions:
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How does using 10 as a benchmark help us compose numbers?
How do we represent a collection of objects using tens and ones? (base 10
blocks, drawing a model, standard form numbers, expanded form)
How can making equal groups of ten objects help us count larger
quantities? (It makes counting quicker)
How can making equal groups of ten objects deepen my understanding of
the base ten number system? (It helps us understand how the system
works or is constructed)
What’s the teacher doing?
What are the student’s doing?
Circulate to monitor for understanding
and ask guiding questions.
Spinning for numbers
Using numbers to construct addition
sentences
Recording addition sentences on
Equation Recording Sheet
Counting the total number on the 0-99
chart
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Phase Two: Explore the Concept
Background
This task is centered on number relations and counting. Students will expand their
basic ideas of place value understanding, which includes base-ten grouping, oral
names, and written names, to relative magnitude. Students should compare one
number to the size relationship of another number much larger, much smaller,
close to or about the same.
Day 4 Activity:
Materials:
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120 chart
Close, Far and In Between resource sheet
A set of four cards with three numerals on each (the numerals should be
from the same row or column found on the 120 chart)
Prior to the lesson, write three numbers on the board for students to analyze,
along with the questions listed below to lead a class discussion. The three
numbers should be from the same row or columns found on the 0-99 chart, but
should not exceed 120 (Example: 62, 67, 69).
• How are the numbers alike? (answers vary) How are they different? (answers
vary)
• Which two are closest? Why? (answers vary)
• Which is closest to 50? To 100? (answers vary)
• Have the students name a number between two of the numbers you have
chosen.
• Name a number that is more than all of the numbers chosen.
• Name a number that is less than all of these numbers chosen.
Part I
Gather students in a common area for a class discussion about the three numbers
provided on the board. The students should use the 120 chart as a reference
when comparing these numbers.
Continue the class discussion with three new numbers for the students to explore
and express their mathematical reasoning.
Part II
In partners, students should go to four stations with one of four cards displayed.
Each card should have 3 numerals and the numerals should be from the same row
of column found on the 120 chart. Students will record the numerals found and
answer the same questions found on the class discussion chart.
After the students have rotated through each of the stations, have the class come
back together to share their findings and express their mathematical reasoning
about their answers and the numerals they have explored.
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Guiding Questions:
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What numerals did you explore? (answers vary)
Did you find any patterns in the numerals you explored? (yes) Which ones?
Explain why the numbers with a five in the ones place are in the same
column. (Because there is a pattern to the 120 chart. All numbers that have
the same number of ones are in the same column.)
Why are the numbers with a five in the tens place in the same row?
(Because there is a pattern to the 120 chart and all numbers that have the
same numeral in the tens place are in the same row.)
What’s the teacher doing?
What are the students doing?
Leading a class discussion and
modeling
Participating in class discussion about
the three numbers provided on board
Asking questions that guide the
discussion and instruction
Using 120 chart as a reference when
comparing numbers
Rotating through the four stations and
recording numerals found
Answering question from previous
discussion
Share findings and express
mathematical reasoning about answers
and numbers explored
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Phase Two: Explore the Concept
Background:
Although the 120 chart is a critical tool to develop students understanding,
students must also realize that the 120 chart is a folded number line. This task is
developed to help students make the connection between a 0-120 chart and
number line. A number line measures distance from zero to any number the same
way a ruler does.
Day 5 Activity:
Materials:
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120 Chart
Tape or glue
2 different colored counters
Spinner (1 more, 1 less, 10 more, 10 less)
Spinner labeled with 10 and 1
Part I
By this time in the year, students should be familiar with a 0-99 chart. Assess prior
knowledge and record what they know and how can use the chart as a tool.
Give each student a 120 chart and have them color each row of ten a different
color. Ask the students what the benefits will be of coloring each row of ten a
different color. After each student has colored their chart, have them cut their 120
chart into strips (0-9, 10-19, 20-29, etc.). Observe which students immediately
start lining strips in order. Praise this concept and ask all students to do the same
thing. After each student has put their number line in order, connect them together.
This is a teacher preference: some teachers like to glue strips together using the
extra flap on the end and some teachers cut the flap off and put a piece of tape on
the back to connect. Either way is fine, however, keep in mind the number lines
will be reused through the unit and year so they will need to be folded up.
Part II
Race to 120 (2 players)
Each player should place their counter on zero. Players will take turns using the
spinner and moving the corresponding number of spaces on the number line.
(Example: if player 1 is on zero, and spins 10 less, they stay on zero. If player 1
spins 1 more, they move their counter to 1 on the number line. If player 2 is on 23
and spins 10 more they move their counter to 33.) The first player to reach the
number 120 or beyond that number wins the game.
What’s the teacher doing?
What are the students doing?
Modeling and asking guiding
questions
Coloring 120 chart and cutting strips
apart
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Gluing strips or 120 chart to create a
number line
Playing Race to 120 with a partner
Answer questions
Phase Two: Explore the Concept (continued from Day 5)
Day 6 Activity (Continued from Day 5):
Part III
Tug-A-War (2 players)
Place the counter at the number 60 on the number line. Player 1 wants the counter
to reach 0 on the number line and player 2 wants the counter to reach 120. One
counter is shared between players and each player takes turn pulling the counter
towards their designated side of the number line.
Player 1 uses the spinner and moves the counter the corresponding number of
spaces towards zero on the number line. (If the chip is on fifty and player 1 spins
10, they move the chip 10 spaces towards the zero) Player 1 must identify and say
the location of the chip on the number line. If player 1 is unable to` identify the
correct location of the chip, it moves back to the previous location.
Player 2 spins and moves the counter that many spaces towards 120. (If the chip
is on 40 and player 2 spins 1, they move the counter to 41) If player 2 is unable to
correctly identify the location of the chip, it moves back to the previous location. If
the chip reaches zero on the number line, player 1 wins. If the chip reaches 120 on
the number line, player 2 wins.
Guiding Questions:
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 What do a 120 chart and a number line have in common? (list numbers
from 1-120, show order of numbers to 120, etc.)
 Can you recognize any patterns on the number line? (numbers with the
same numeral in the tens place are in the same row, numbers with the
same numeral in the ones place are in the same column)
 What strategy are you using to move forward or backwards by 10 or 1?
(counting on, counting backwards, etc.)
What’s the teacher doing?
What are the students doing?
Modeling and asking guiding
questions
Playing Tug-a-War with a partner
Answer questions
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Phase Two: Explore the Concept
Background:
On a conventional 120 chart, each row below the previous is greater than the one
above. It can be conceptually hard for many children to understand that when you
move down, the numbers actually get bigger. Using the Number Hotel will allow
students to make the connection that as the height of the hotel increases so do the
numbers in general.
Day 7 Activity:
Materials:
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Number Hotel game board
Arrow cards
Counters to use on the game board
Gather the students together to compare and analyze the Number Hotel and the
120 Chart. Have the students participate in a class discussion which includes
reviewing and finding new patterns. Ask questions, rather than pointing out the
differences, to prompt students to explain their discoveries of the Number Hotel,
such as:
• What differences do you notice between the Number Hotel and the 120
Chart?(on a 0-120 chart the numbers go from smallest to largest)
• In what ways are they the same? (They show most of the same numbers)
• What strategies might you need to know in order to use the Number Hotel?
(counting backwards)
Part II
Pair the students into partner groups to play I’m Checking Out using the Number
Hotel game board.
To Play: There are two exits out of the Number Hotel. The students must exit the
hotel through the 0 door or the 119 door. Each player will place a counter on
numeral 60 on their own game board. Using the stack of arrow cards, players will
turn over five arrow cards each. The arrow cards can be arranged in any order for
the player to find the quickest way to get out of the building. Each arrow
represents one move on the Number Hotel game board. Players may move up,
down, left or right. Once the players have moved five spaces, they may turn over
five more arrow cards. Play stops and the player closest to their door wins.
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Unit 8; 1st Grade; Foundation of Numbers up to 99
Part III
Gather the students together for a class discussion about what was learned from
the Number Hotel. Have the students reflect on any connections they have made
between the 0-120 chart and the Number Hotel. Have the students record what
they learned in their math journals.
Guiding Questions:
• How is the Number Hotel different from the 120 chart? (on a 120 chart the
numbers go from smallest to largest)
• How is the Number Hotel the same as the 120 chart? (They show most of the
same numbers)
• What new patterns did you find in the Number Hotel? (answers vary)
• Does the order of the arrows change where you would end up? (yes)
• What strategy did you use to make it as close as you could to the door? (answers
vary)
• What would you do differently if you could play again? (answers vary)
What’s the teacher doing?
What are the students doing?
Leading a class discussion and posing Participate in class discussion
guiding questions
Play game I’m Checking Out with a
Modeling how to play I’m Checking
partner
Out
Answer debriefing questions after game
Gather students after the game is over
and ask debriefing questions
Phase Three: Explain the Concept and Define the Terms
Background:
An important variation of the grouping activities is aimed at the equivalent
representations of numbers. Students need to be able to think flexibly about
numbers. Many students have a difficult time understanding that 10 is actually a
unitization of 10 ones. For example: most students will see 21 as a 2 groups of ten
and 1 one, which is correct, however they must also begin to see that 21 is also 1
ten and 11 ones. This flexible view of number supports strategy development later.
Day 8 Activity:
Materials:
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120 Chart
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Unit 8; 1st Grade; Foundation of Numbers up to 99
 Base 10 blocks
 10 frames
 Place value disks
 Folder (to hide riddle)
Gather students in a common area and present several riddles to them. Allow
student access to base ten blocks, ten frames, bean sticks, dot sticks, or any other
manipulative that allows them to see numbers and quantities as tens and ones.
Create several base ten riddles for students to solve using the manipulatives.
Sample riddles:
• I have 2 tens and 1 one. What number am I?
• I have 6 ones and 3 tens. What number am I?
• I have 3 tens and 11 ones. What number am I?
Have students share how they solved the mystery riddle. Once students are
comfortable with the concept, have them work in pairs to solve the riddles.
Once students are familiar with concept and have solved various teacher prepared
riddles, have them create a riddle of their own using the base ten blocks, bean
sticks, or dot sticks. They can do this with a partner. One partner will create a
riddle and hide it from the view of their partner. He or she will then describe what
their number looks like (example: I have 3 tens and 4 ones). The other partner
tries to solve the mystery riddle. If they are correct, they switch roles.
This task should be continued throughout the unit and revisited throughout the
year. To meet the needs of all students, the complexity of the riddles should
increase, in addition to the quantity of the mystery number. Examples of how to
increase the complexity of riddles:
• I am 32. I have 12 ones. How many tens do I have? (2)
• I have 22 ones. I am between 80 and 90. How many tens do I have? (6)
Student-created riddles can be placed in a center to allow other classmates to
solve them.
Guiding Questions:
• How many ones make up the mystery number? (answers vary)
• How many groups of ten make up the mystery number? (answers vary)
• What strategy did you use to solve the mystery riddle? (answers vary)
Possible Extension:
The complexity of the riddles and how they are presented to students can easily
extend this lesson. Allowing students to create riddles that do not list numbers as
only tens and ones gives great insight into the student’s understanding of numbers
and how they can represent numbers in multiple ways
16 of 20 Page
Unit 8; 1st Grade; Foundation of Numbers up to 99
Vocabulary to define and discuss:
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Compare numbers – to consider the value of two numbers to determine
which number is greater or less or if the numbers are equal in value
Compose numbers – to combine parts or smaller values to form a number
Counting (natural) numbers – the set of positive numbers that begins at
one and increases by increments of one each time {1, 2, 3, ..., n}
Decompose numbers – to break a number into parts or smaller values
Digit – any numeral from 0 – 9
Expanded form – the representation of a number as a sum of place values
(e.g., 119 as 100 + 10 + 9)
Numeral – a symbol used to name a number
Open number line – an empty number line where tick marks are added to
represent landmarks of numbers, often indicated with arcs above the
number line (referred to as jumps) demonstrating approximate proportional
distances
Order numbers – to arrange a set of numbers based on their numerical
value
Period – a three-digit grouping of whole numbers where each grouping is
composed of a ones place, a tens place, and a hundreds place, and each
grouping is separated by a comma
Place value – the value of a digit as determined by its location in a number
such as ones, tens, hundreds, etc.
Standard form – the representation of a number using digits (e.g., 118)
Whole numbers – the set of counting (natural) numbers and zero {0, 1, 2,
3, ..., n}
What’s the teacher doing?
What are the students doing?
Provide manipulatives that allow
student to see numbers and quantities
as hundreds, tens, and ones
Solving riddles using manipulatives
Work with a partner to create and solve
riddles
Create riddles for students to solve
using manipulatives
Facilitate discussion of how students
are solving riddles
Ask guiding questions
17 of 20 Page
Unit 8; 1st Grade; Foundation of Numbers up to 99
Phase Four: Elaborate on the Concept
Background:
This task is centered on number relations and counting. Using number lines
allows students to see how one number is related to another.
Day 9 Activity:
Materials:
 120 chart
 Student dry erase boards or paper and pencil
Part I
Draw a number line labeled with only a 0 and 120 on the board. The number line
should be labeled 0 at one end and 120 at the other.
Gather students together to have a class discussion about the number line
provided on the board. Draw an arrow to a spot on the number line and have
students guess the mystery number. With each student’s guess, have the students
identify why they chose that particular number and what their strategy was. Write
that number on the number line as it relates to the mystery number. As students
guess the mystery number have a volunteer also identify that number on the 120
chart, so students can make the connection between the number line and 120
chart. Continue to record the student guess until the mystery number has been
revealed. Be sure that students explain why they are choosing a particular
number.
Part II
Have the students play the mystery number game with a partner using dry erase
boards or paper and pencil. Let each student have a chance creating a mystery
number, as well as guessing a mystery number.
Guiding Questions:
• What was the mystery number? (answers vary)
• How many guesses did you need to find the mystery number? (answers vary)
• What strategy did you use to correctly identify the mystery number? (answers
vary)
• What was the hardest number to guess? Why? (answers vary)
18 of 20 Page
Unit 8; 1st Grade; Foundation of Numbers up to 99
Differentiation:
Extension
• Have the students extend their number lines to try 200, 300 or 400.
Intervention
• Have students complete the task in a small group to closely monitor the student’s
work. Students can also hold a 0-99 chart in their hand to help suggest what the
mystery number could be.
What’s the teacher doing?
What are the students doing?
Drawing the number line
Guess the number
Facilitate discussion about the number Play mystery number game with a partner
line
Record student’s guesses on the
number line
Circulate around the classroom as
pairs of students play the mystery
number game
19 of 20 Page
Unit 8; 1st Grade; Foundation of Numbers up to 99
Phase Five: Evaluate Student Understanding of the Concept
Day 10 Activity:
Provide variety of counting manipulatives. Orally present the following real-world
situations and tasks:
1) The City of Funville offers several day camps for children during the
summer. The flyer used to advertise the camps is shown below. Use
the flyer to complete the following tasks:
2)
a) Record the cost of Nature Camp using expanded form.
b) Create concrete or pictorial models to represent the cost of Nature Camp in two
different ways.
c) Which camp’s cost could be represented using 1 hundred and 2 ones?
d) The City is thinking about adding a Crafts Camp. The cost of the Crafts Camp
will be more than Princess Camp but less than Lego® Camp. What amount could
be the cost for the Craft Camp? Represent this amount in standard and expanded
form.
e) Order the cost of the Lego®, Sports, Princess, and Nature camps from least
expensive to most expensive. Represent the order of the camp costs using an
open number line.
f) Use symbols to represent the comparison of the two least expensive camps.
g) Orally explain how place value was used to compare and order the camp costs.
What’s the teacher doing?
What are the students doing?
Providing manipulatives
Completing assessment as instructed by
the teacher
Facilitating assessment
20 of 20 Page