MATH MESSAGE
3RD GRADE
MATH
Unit 2: Place Value and Problem Solving with
Units of Measure
Math Parent Letter
The purpose of this newsletter is to guide
parents, guardians, and students as students
master the math concepts found in the St.
Tammany Public Schools’ Guaranteed
Curriculum aligned with the state mandated
Common Core Standards. Third grade Unit 2
teaches Place Value and Problem Solving with
Units of Measure. This newsletter will address
concepts found in Unit 2, Lessons 1-5: Time
Measurement and Problem Solving.
Words to know
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Analog Clock
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Continuous
Halfway
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Intervals
Minutes
Number line
Point
Plot (plotting)
Seconds
Objective of Lessons 1-5
 Explore
1
time as a continuous
measurement using a stopwatch.
 Relate
2
skip-counting by fives on the clock
and telling time to a continuous
measurement model, the number line.
 Count
3
by fives and ones on the number
line as a strategy to tell time to the
nearest minute on the clock.
 Solve word problems involving time
intervals within 1 hour by counting
backward and forward using the number
line and clock.
 Solve word problems involving time
intervals within 1 hour by adding and
subtracting on the number line.
Lessons 1-5:
Time Measurement and Problem Solving
Things to Remember!
When drawing the hands on a clock, the minute
hand must be longer than the hour hand. When
reading a clock and looking at the hour hand,
the hour will always be the number that the
hour hand has passed or is directly on.
Time Measurement and Problem Solving
Ariel has 9 math problems on her test. It takes
her 3 minutes to complete each problem. How
many minutes does it take Ariel to finish all 9
problems?
9 x 3 minutes
= 27 minutes
It takes Ariel
27 minutes to
finish her test.
Lessons 2-3:
In Lesson 2, students use a number line to
understand that time is a continuous unit of
measurement. Students apply what they learn
about skip-counting by fives to telling time on a
number line. They learn how to read/draw a
number line with hours as endpoints and
minutes in multiples of five. In Lesson 3,
students begin to use a number line that is
divided into one-minute intervals.
Number line
Number line from 7:00a.m.-8:00a.m. counting
by fives
Number line from 7:00a.m-8:00a.m. showing
minutes
How you can help at home?
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Ask your child to tell time using an analog clock.
Ask your child how many minutes have passed
since we got home (and other situations).
Ask your child how many minutes between two
times within the hour.
Example of plotting time on the number
line:
On the number line, plot a point for the time
show on the clock. Draw a line to match the
clocks to the point.
Example of skip count, then count on:
5, 10, 15, 20,
25, 30, 31, 32
so the time is
5:32
Example of using a number line to solve a
problem with the end time and minutes
elapsed known and the start time unknown.
Drew finished practicing piano at 4:52p.m. He
practiced for 45 minutes. What time did he start
practicing piano?
We count back 45 minutes, so we count 2 to get
to 10 (a benchmark number), then 40, then 3
more.
Example of using a number line to solve a
problem with the start time and minutes
elapsed known and the end time is
unknown.
Adrien began his homework at 3:15 a.m. He
worked for 23 minutes. What time was it when
he ended?
Example of using a number line to solve a
problem:
Students will draw number lines to represent
and solve problems with time.
Kendra and Keisha started reading at 7:00 a.m.
The clock and the number line show the times
they stopped reading. Who finished first? How
do you know?
Kendra
We count forward 27 minutes, so we skip-count
to 25 and then add on 26, 27.
Example of using a number line to solve a
problem with the start and end time known
and elapsed time is unknown.
Keisha
Kendra finished at
7:47 and Keisha
finished at 7:57.
Kendra finished
reading first because
7:47 comes before
7:57.
Andre started cleaning his room at 6:20p.m. and
stopped cleaning his room at 6:53p.m. How
many minutes did Andre clean his room?
We need to begin counting at 6:20 p.m. and
stop counting at 6:53 p.m., so we count 5, 10,
15, 20, 25, 30, 31, 32, 33.