bake sale cookies! finding multiple sets of fractional amounts

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BAKE SALE COOKIES! FIN DING MULTIPL E SE T S OF FRACTIONAL AMO UNTS

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Page 1: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

BAKE SALE

COOKIE

S!

F I ND

I NG

MU

LTI P

L E S

ET

S O

F FR

AC

TI O

NA

L

AM

OU

NT

S

Page 2: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

How do you use what you know about whole numbers to help you multiply a fraction??3 x ?

Page 3: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

DECOMPOSITION

What are some ways we could decompose:

25?100? ?

Page 4: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

DECOMPOSITION

Like whole numbers, fractions can be decomposed. Example:

Here the fraction is decomposed into unit fractions. Let’s see how that can help us solve other problems.

= + +

Page 5: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

BAKE SALE!

I have to make a lot of cookies for an upcoming bake sale at our Spring

Fling and realized I need to make four batches of my

favorite recipe. While scanning the recipe I saw there were some fraction

amounts …

Page 6: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

BAKE SALE!

Let’s focus on the granulated sugar. How much is needed for one recipe? Is that all that is needed for the bake sale? Why or why not?What number sentence could be used to find how much total granulated sugar is needed?

Page 7: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

CALCULATING SETS OF

For granulated sugar I would need:3 sets of cup or 3 x

What is another way to write that using only unit fractions?3 x ( ) or:

What does that look like on a number line?

+ ++ + +++ +

+ +

Page 8: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

Core Lesson

0 1 2 3 4

+ + + ++ + ++ How much is that?

Page 9: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

Core Lesson

I would need or 2 cups ofgranulated sugar.

So 3 sets of 3 parts of 4 is 9 parts

total

3 x = 3 x 3 1 = 9x 1 = 9 4 4 4

Page 10: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

PRACTICE

Designing costumes for an upcoming performance, the music teacher determined the lead singers’ costumes needed 5/8 of a yard of ribbon. If there are 3 lead singers, how much total ribbon is needed? Write an equation to represent the situation and explain your thinking.

Page 11: BAKE SALE COOKIES! FINDING MULTIPLE SETS OF FRACTIONAL AMOUNTS

MORE PRACTICE