Multiplication to Divide With 8 and 9

Key Concepts

• Multiplication facts to divide with 8.
• Multiplication facts to divide with 9.

The Relation between multiplication and division:

Multiplication and division are closely related, given that division is the inverse operation of multiplication.

When we divide, we look to separate into equal groups, while multiplication involves joining equal groups.

• If we have 8 x 8 = 64, its inverse relations (in the form of a division) will be the following:
  64 ÷ 8 = 8.
• If we have 9 x 7 =63, its inverse relations (in the form of a division) will be the following:
  63 ÷ 9 = 7.

4.4.1 Multiplication Facts to Divide with 8.

Example 1:

An art teacher has 72 crayons. The crayons came in boxes with 8 crayons in each box. Find the total number of boxes of crayons.

Solution:

Find 72 ÷ 8.

One box has 8 crayons.

What times 8 equals 72?

8 x 9 = 72.

9 boxes of crayons were there.

Another way:

Example 2:

Sandy bought 64 cookies to put into packages. One package holds 8 cookies. How many total packages will be made?

Solution:

Find 64 ÷ 8.

What times 8 equals 64?

8 x 8 = 64.

8 packages will be made.

Another way:

8 packages will be made.

Example3:

A grocer has 56 oranges that need to be bagged. He kept 8 oranges in one bag. How many bags were the grocer using?

Solution:

Find 56 ÷ 8.

What times 8 equals 56?

8 x 7 = 56.

7 bags are used.

Another way:

7 bags are used.

4.4.2 Multiplication Facts to Divide with 9.

Example1:

Sports teacher divides 81 students into 9 groups of dance teams. How many students are in each group?

Solution:

81÷ 9.

   ______ students in one group.

9 times what number is 81?

9 x 9 = 81.

9 students are there in one group.

Another way:

9 students are there in one group.

Example 2:

here were 72 contestants in a bicycle race. The riders were divided into 9 equal groups. Find the number of riders in each group.

Solution:

72÷ 9.

______ students in one group.

9 times what number is 72?

9 x 8 = 72.

8 riders are there in one group.

Exercise:

1. What multiplication fact can you use to find 27 ÷ 9?
2. Find each quotient.
   a. 48 ÷ 8.
   b. 36 ÷ 9.
3. Use the multiplication equation to help find each quotient.
   45 ÷ 9=?
   What number times 9 is 45?
   ____ x 9 = 45
   45 ÷ 9 =          ______.
4. Fill in the missing numbers to complete the fact family.

5. Find each quotient.

a.

b.

6. Identify dividend, divisor, quotient.

7. Complete each family of facts.

8. Tom had 63 apples. He divides apples to his 9 friends. Find the number of apples did Tom give to each of his friends?

9. A glass pitcher contains 63 ounces of juice which is poured equally into 9 glasses. Find ounces of juice does each glass contain?

10. Juliet has 64 candy bars which she splits equally among 8 of her cousins. How many candy bars does each of Juliet’s cousins get?

Concept map:

What have we learned:

• Understand how to use multiplication facts to divide with 8. 
• Understand how to use multiplication facts to divide with 9.
• Understand how to find quotient.
• Identify dividend, divisor, quotient.