Lesson 8 Relate Quotients to Familiar Products

- Let’s consider the products and quotients we know right away or can find quickly.

Warm-up Number Talk: Multiplication and Division

Find the value of each expression mentally.

$4 \times 10$
$40 \div 4$
$40 \div 10$
$60 \div 6$

Activity 1 Card Sort: Multiplication

Quiz your partner on their multiplication facts. Sort your partner’s facts into one of these columns:
1. know it right away
2. can find it quickly
3. don’t know it yet
Multiplication expressions I’m going to practice:

Activity 2 If I Know, Then I Know

Students working with partners, playing a math game.

If I know $4 \times 5 = 20$ , then I know .

Set the multiplication fact cards in a stack face down.
Take turns drawing a multiplication fact card.
Use the multiplication fact on the card to record a multiplication equation in the “If I know …” column.
Then, record related division equations in the “Then I know …” column.

If I know …	then I know …

If I know …	then I know …

Practice Problem

Problem 1

For each multiplication equation, write a related division fact you know from the multiplication equation.

$8 \times 5 = 40$
$2 \times 9 = 18$