1. 5th Grade Module 3 – Lesson 13 Designed by Leigh-Ann Pieragostini
Lesson 13: I can use fraction benchmark numbers to assess reasonableness of addition and subtraction equations.
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

2. Let’s Say Fractions as Decimals
Say the fraction in unit form
Say the fraction in decimal form
1 tenth
Zero point one
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

3. Say the fraction in decimal form.
3 and 1 half
1 half
5 tenths
3 tenths
three point five
Zero point five
Zero point five
Zero point three
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

4. Is the sentence true or false?
Write the answer that makes the addition sentence true.
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

5. Is the sentence true or false?
Re-write the addition sentence using like units.
TRUE
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

6. Is the sentence true or false?
Re-write the subtraction sentence using like units.
TRUE
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

7. Is the sentence true or false?
Write the sentence that will make the sentence true
FALSE
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

8. 5th Grade Module 3 – Lesson 13 Designed by Leigh-Ann Pieragostini
Application Problem
Solution on next slide…
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

9. 5th Grade Module 3 – Lesson 13 Designed by Leigh-Ann Pieragostini
Solution
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

10. Concept development
We are going to think about solving this problem without using paper & pencil. Use reasoning and share with your partner an estimate.
Think: Will it be more than a whole? Can you think about what the fractions represent as cents?
Have students share estimates and strategies.
Click for solution.
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

11. Do you think the answer is more or less than one?
Problem 2
Without calculating, what do you know about the value of this expression?
Talk to your partner.
Do you think the answer is more or less than one?
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

12. 5th Grade Module 3 – Lesson 13 Designed by Leigh-Ann Pieragostini
Problem 3
Use your reasoning skills to decide if the sum is more than or less than 1. Decide with your partner.
Is 4/10 more than 1 half or less than 1 half?
Is 4/10 closer to 0 or 1 whole?
What’s half of 10 tenths?
How much money is 4 tenths?
Is 1/3 closer to 0 or 1 whole?
Is 1/3 more than 1 half or less than 1 half?
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

13. 4 10 + 2 9 Share your analysis of this expression with your partner.
Problem 4
Share your analysis of this expression with your partner.
Is the answer less than or greater than ½?
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

14. 1 4 7 − 9 10 Think about this expression with your partner.
Problem 5
1 4 7 − 9 10
Think about this expression with your partner.
Don’t forget to look at the operation!
Is the value going to be greater than or less than ½?
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

15. 4 5 − 1 8 Reason with your partner about this problem.
Is the value of the expression more than ½ or less?
Is 4/5 more than ½ or less than ½?
Is 4/5 closer to 0 or 1 whole?
What’s half of 5 fifths?
Can you convert 4/5 to tenths or a decimal in your head? What is it?
Is 1/8 more than ½ or less than ½?
Is 1/8 closer to 0 or 1 whole?
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

16. 2 1 3 +3 1 5 ___ 6 + 7 8 Compare these two expressions. <, >, =
Problem 7
___
Compare these two expressions.
<, >, =
Reason your answer using estimation.
*click to reveal answer
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

17. 4 9 10 −1 1 8 ___ 2 1 2 + 2 7 Compare these two expressions.
Problem 7
−1 1 8 ___
Compare these two expressions.
<, >, =
Reason your answer using estimation.
Watch your signs!!!
*click to reveal answer
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

18. Get Ready to Complete the Problem Set on Your Own!
Complete Pages 3.D.12 & 3.D.13 You will have minutes to work. Try your Best!
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

19. 5th Grade Module 3 – Lesson 13 Designed by Leigh-Ann Pieragostini
LET’S Debrief
Bring your Problem Set to the Debrief. Share, check, and/or explain your answers to your partner.
What did you learn today?
Why do mathematicians agree it is wise to estimate before calculating?
Think about what happens to your reasoning when you are calculating.
Why might it be wise to estimate after calculating too?
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini

20. 5th Grade Module 3 – Lesson 13 Designed by Leigh-Ann Pieragostini
EXIT
TICKET
Page 3.D.14
5th Grade Module 3 – Lesson Designed by Leigh-Ann Pieragostini