Lesson 10 Concepts of Division

- Let’s think about the size of quotients.

Warm-up Number Talk: Same Dividend, Different Divisor

Find the value of each expression mentally.

$120 \div 12$
$120 \div 6$
$120 \div 3$
$120 \div 2$

Activity 1 Share Pretzels

Order the situations from greatest to least based on the number of pretzels each student will get. Be prepared to explain your reasoning.

3 students equally share 42 pretzels.
14 students equally share 42 pretzels.
3 students equally share 24 pretzels.
3 students equally share 45 pretzels.
7 students equally share 42 pretzels.
3 students equally share 6 pretzels.
6 students equally share 42 pretzels.

Activity 2 Division Patterns

Problem 1

Find the value of each expression.

$36 \div 3$
$12 \div 3$
$9 \div 3$
$6 \div 3$
$3 \div 3$
$1 \div 3$

Problem 2

What patterns do you notice?
Why is the quotient getting smaller?
What do you know about this expression: $\frac{1}{3} \div 3$ ?
Draw a diagram to represent $\frac{1}{3} \div 3$ .

Practice Problem

Problem 1

For each pair of expressions, decide which is greater. Explain your choice without calculating the value of the expressions.

$210 \div 3$ $210 \div 5$
$210 \div 3$ $75 \div 3$