Grade 2
Lesson: 11.9
Reference to English
Problem Solving: Use Logical
Reasoning
Math Standard(s): 2.NBT.7
Domain: Numbers and Operations in Base Ten
Content objective(s):
Language Objective(s):
Students will use logical reasoning to solve problems.
Students will listen to story problems with 3 clues in them and
I can solve story problems.
solve the problems.
I can listen to story problems with 3 clues and solve the problems.
Essential Understanding:
Required Academic Vocabulary for Word Wall:
Some problems can be solved by reasoning about the
Listen:
conditions in the problems.
Read:
Write:
Speak:
Sentence Frame:
Materials:
 Piggy bank or drawing of one on the board.
Additional Lesson Vocabulary:
piggy bank, pennies,
Lesson:
Instructional Time: 25 – 30 minutes
Opening: (1 minutes)
T: “You have learned ways to find sums of three-digit numbers. Today, you will be learning how to use addition of three-digit
numbers to solve a problem.”
Introduction to New Material (Direct Instruction): (15 minutes)
 Pass out whiteboards, erasers and markers.
T: “I am going to tell you a story problem and I need you to write down the important information on your whiteboard.”
T: “Your friend wants you to guess how many pennies she has in her piggy bank. She makes up the following clues.
T: “Clue #1: I have between 400 and 500 pennies. You might want to write that information down like this.”
 Write 400-500 on the board.
T: “Clue #2: I have an even number of pennies. So she has an even number not an odd number.”
T: “Clue #3: The number of pennies is the sum of two of the following numbers: 382, 126, 272, 193, 356. Write those numbers
on the board like this.”
T: “What are the two numbers?”
T: “I want to start with the 2nd clue. It said the number of pennies is even. So which number can I cross out?”
S: “193.”
T: “Yes, tell your neighbor why.”
S: “because it is an odd number.”
T: “Yes, because it is an odd number and all the other numbers are even, so any thing added to it would become odd.”
T: “Now we should start adding numbers together. We know that the number is between 400 and 500. So it can’t be 382 plus
356, that number would be over 700.”
T: “What is 382 plus 126. Add it on your boards and then show me your boards.”
S: will add 382 plus 126.
T: “Show me your boards. Yes, 382 plus 126 equals 508. Is that between 400 and 500?”
S: “no.”
T: “Since 126 is the lowest number when can determine that 382 plus any of the other numbers is more than 500. We can cross
out 382.”
T: “We have 126, 272 and 356 left.”
T: “Will you add 126 plus 272 on your boards.”
S: will add 126 plus 272 equals 389.”
T: “Read the number sentence to your neighbor and check your answers.”
T: “126 plus 272 equals 389. That is less than 400. That doesn’t work.”
T: “What about 126 plus 356. Add those two numbers on your board.”
S: will add 126 plus 356 equals 482.
T: “Show me your boards. Good, now check your answer with your neighbor.”
T: “126 plus 356, let’s add it together.”
 Add the numbers together showing regrouping.
T: “126 plus 356 equals 482.”
T: “Is that our answer? Is it between 400 and 500?”
S: “yes”
T: “Is it an even number?”
S: “yes”
T: “Did it use two of the given numbers?”
S: “yes.”
T: “I think we found our answer! Should we add the last two numbers just to see if there are two answers?”
 Add the last two 272 plus 356.
T: “I am going to tell you another story with clues. You need to write down the important information and then we will solve it
together.”
T: “I have more than 600 pennies. I have an odd number of pennies. MY number of pennies is the sum of two of the following
numbers: 348, 173, 328, 296, 257.”
 Solve the problem the same as the previous problem.
T: “Time for another problem, but I want you to do more of this one on your own. Remember to write down the important
information.”
T: “Carmen used small shells to make some necklaces. (draw a necklace on the board) She used an even number of shells. The
number of shells is between 300 and 400. The number of shells is the sum of two of the following numbers: 260, 187, 216, 254,
158.”
 If the students are getting it, allow the to complete the problem on their own. If they are still struggling walk them through it
like you did on the first one.
T: “What are the two numbers?”
Closing: (4 minutes)
T: “Last problem of the day. I will read it and you will solve it!”
T: “Sara saved some stamps. (Draw a stamp on the board) She saved more than 300. She saved an even number of stamps. The
number she saved is the sum of two of the following numbers: 149, 162, 157, 128, 135.”
 If the students are getting it, allow the to complete the problem on their own. If they are still struggling walk them through it
like you did on the first one.
T: “What are the two numbers?”
Assessment:
Story Problems observation