Lesson 11 Divide Unit Fractions by Whole Numbers

- Let’s divide a unit fraction by a whole number.

Warm-up Number Talk: Double the Divisor

Find the value of each expression mentally.

$72 \div 4$
$36 \div 4$
$4 \div 4$
$1 \div 4$

Activity 1 More Macaroni and Cheese

Jada and her 2 sisters equally share $\frac{1}{2}$ a pan of macaroni and cheese.

Draw a diagram to represent the situation.
Explain how this expression represents the situation: $\frac{1}{2} \div 3$
How much of the whole pan of macaroni and cheese will each person get?

Activity 2 More People Share

Problem 1

4 people equally share $\frac{1}{2}$ a pan of macaroni and cheese.

Draw a diagram to represent the situation.
Explain how your diagram represents $\frac{1}{2} \div 4$ .
How much of the whole pan of macaroni and cheese did each person get? Be prepared to explain your reasoning.

Problem 2

5 people equally share $\frac{1}{2}$ a pan of macaroni and cheese.

Draw a diagram to represent the situation.
Explain how your diagram represents $\frac{1}{2} \div 5$ .
How much of the whole pan of macaroni and cheese did each person get? Be prepared to explain your reasoning.

Problem 3

How are the problems the same? How are they different?

Practice Problem

Problem 1

A pan of macaroni and cheese is $\frac{1}{3}$ full. Four friends split the remaining macaroni and cheese equally.

Make a drawing that represents the situation.
Write a division expression representing how much of a pan each friend gets.
Explain how the drawing shows the division expression.