Lesson 16Objective: Solve word problems

using tape diagrams and fraction-by-fraction multiplication.

By the end of the lesson, you will be able to…

5th Grade Module 4– Lesson 16K. Clauson

Multiply Fractions

(More review of lessons 13, 14, & 15. Option may be to skip this part of the lesson.)

Multiply Whole Numbers by Decimals

Use worksheet as warm up/ fluency practice for this part of the lesson!

What patterns do the students notice?

Problem 2 Joakim is icing 30 cupcakes. He spreads mint icing on 1/5 of the cupcakes and chocolate on 1/2 of the remaining cupcakes. The rest will get vanilla frosting. How many cupcakes have vanilla frosting?

Let’s use a tape diagram to model this problem.

Concept Development- Students will use the Problem Set for this lesson!

Problem 2 Joakim is icing 30 cupcakes. He spreads mint icing on 1/5 of the cupcakes and chocolate on 1/2 of the remaining cupcakes. The rest will get vanilla frosting. How many cupcakes have vanilla frosting?

Let’s think of this problem another way.

Concept Development- Students will use the Problem Set for this lesson!

When we labeled the 1 fifth for the mint icing, what fraction of the cupcakes were remaining?

What does Joakim do with the remaining cupcakes?

1 half of 4 fifths

Problem 2 Joakim is icing 30 cupcakes. He spreads mint icing on 1/5 of the cupcakes and chocolate on 1/2 of the remaining cupcakes. The rest will get vanilla frosting. How many cupcakes have vanilla frosting?

What is ½ of 4 fifths?

So, 2 fifths of all the cupcakes got chocolate, and 2 fifths of all the cupcakes got vanilla. The question asked us how many cupcakes got vanilla icing. Let’s find 2 fifths of all the cupcakes which is 2 fifths of 30. Work with your partner to solve.

This time, let’s imagine that Joakim put mint icing on 2 fifths of the cupcakes. Draw another tape diagram to show that situation.

Concept Development- Students will need their whiteboards for this question.

What fraction of the cupcakes are remaining this time?

Let’s confirm that there are 9 cupcakes that got vanilla icing by using fraction multiplication. How might we do this?

Turn and talk.

Complete Problem 1 and 3 on your own. You must use a tape diagram to solve. Check your work with a neighbor when you’re finished!

Problem 1 Solution

Problem 3 Solution

Problem 5 Milan puts 1/4 of her lawn-mowing money in savings and uses 1/2 of the remaining money to pay back her sister. If she has $15 left, how much did she have at first?

• How is this problem different than the ones we just solved?– This time we do not know what the whole is. We know

how much money she has left, but we have to figure out what she had at the beginning. We have to work backwards.

– The other problems were whole to part. This time it is part to whole.

Let’s draw a tape diagram!

Problem 5 Milan puts 1/4 of her lawn-mowing money in savings and uses 1/2 of the remaining money to pay back her sister. If she has $15 left, how much did she have at first?

• Let’s check our work by using a fraction of a set. What multiplication sentence tells us what fraction all her money Milan gave to her sister? What fraction did she give to her sister?

1 X 3 = 32 4 8

So what is 3/8 of $40?

Complete Problem 4 and 6 on your own. You must use a tape diagram to solve. Check your work with a neighbor when you’re finished!

* Fast Finishers- do #7!

Teacher tip: #6 is challenging! You may want to complete that one as a whole class!

Problem 4 Solution

Problem 6 Solution

Get Ready to Finish theProblem Set on Your Own!

Problem Set was completed in the lesson today!

-----------------------------------------------------------------Fast finishers:- Math Center Activities- choice boards,

extra Sprint challenge- CML packets/ worksheets- Problem Solving pages

5th Grade Module 4– Lesson 16K. Clauson

5th Grade Module 4- Lesson 16K. Clauson

LET’S DEBRIEF

• Take 2 minutes to check your answers with your partner.• Let’s share any insights you had while solving these problems.

5th Grade Module 4– Lesson 16K. Clauson

EXITTICKETLESSON 16