# 1.06 Multiplication and division by 10's, connecting to place value

Lesson

## Ideas

Do you remember how to use  models to represent place value  ?

### Examples

#### Example 1

Use the least amount of blocks possible to make the number 530.

Worked Solution
Create a strategy

Write the number in a place value table. Recall that each kind of block represents a different place value.

Apply the idea

Write the number 530 in this place value table.

The place value table tells that 530 has 5 hundreds, 3 tens, and 0 units. So the blocks below make 530.

Idea summary

A place value table is useful to find how many blocks are needed to make a number.

## Multiply or divide by ten

By remembering that each digit in our number is ten times larger than the place to its right, we can multiply or divide by 10.

### Examples

#### Example 2

Complete these number sentences.

a

9 \times 10 = ⬚

Worked Solution
Create a strategy

Remember that each column in the place value table is 10 times larger than the one to its right.

When multiplying a number by 10, all the digits move to the left one column in the place value table.

Apply the idea

Here is 9 in a place value table:

When we multiply by 10, the 9 moves to the left in the table and we use 0 as a place holder.

9 \times 10 = 90

b

90 \times 10 = ⬚

Worked Solution
Create a strategy

Remember that each column in the place value table is 10 times larger than the one to its right.

When multiplying a number by 10, all the digits move to the left one column in the place value table.

Apply the idea

Here is 90 in a place value table:

When we multiply by 10, the 3 and 0 move to the left in the table and we use 0 as a place holder.

90 \times 10 = 900

c

900 \times 10 = ⬚

Worked Solution
Create a strategy

Remember that each column in the place value table is 10 times larger than the one to its right.

When multiplying a number by 10, all the digits move to the left one column in the place value table.

Apply the idea

Here is 900 in a place value table:

When we multiply by 10, the 3 and 0s move to the left in the table and we use 0 as a place holder.

900 \times 10 = 9000

d

9000 \times 10 = ⬚

Worked Solution
Create a strategy

Remember that each column in the place value table is 10 times larger than the one to its right.

When multiplying a number by 10, all the digits move to the left one column in the place value table.

Apply the idea

Here is 9000 in a place value table:

When we multiply by 10, the 3 and 0s move to the left in the table and we use 0 as a place holder.

9000 \times 10 = 90\,000

Idea summary

When we multiply by 10, our number becomes ten times bigger, so the digit moves to the next highest place, by moving left.

When we divide by 10, our number becomes ten times smaller. so the digit moves one place right.

### Outcomes

#### MA2-5NA

uses mental and written strategies for addition and subtraction involving two-, three-, four and five-digit numbers

#### MA2-6NA

uses mental and informal written strategies for multiplication and division