The amount in the tens place goes up by one and we get a result of\,30. The units value does not change. We add ten again to complete the pattern by adding 1 to the tens place each time.

The complete pattern is 20,\,30,\,40,\,50,\,60.

Idea summary

When adding 10 each time in the pattern, the units digit does not change and the tens digit increases by 1.

Multiply numbers by 10

Let's look at how to multiply numbers by 10.

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Examples

Example 2

Find the value of 10\times 4.

Worked Solution

Create a strategy

We can think of 10\times 4 as 10 groups of 4 just like in the image below that has 10 groups of 4 squares:

Apply the idea

The above shape has 40 squares in total.

\displaystyle 10\times4

\displaystyle =

\displaystyle 40

Reflect and check

We can also use a place value table and increase the place value of the 4.

The number 4 has a 4 digit in the units column:

Tens	Units
	4

But when we multiply 4 by 10, the 4 moves up in place value to the tens.

Tens	Units
4

To have the correct value we put a place holder of 0 in the units column.

Tens	Units
4	0

So we get: 10\times 4=40

Idea summary

A quick way to multiply any whole number by 10 is to add a 0 at the end.

That moves all our numbers up one place in the place value table, with the 0 as a place holder in the units column.

However, this rule is ONLY true for whole numbers, so you have to be careful once fractions or decimals are involved.

Outcomes

AC9M3N04

multiply and divide one- and two-digit numbers, representing problems using number sentences, diagrams and arrays, and using a variety of calculation strategies

AC9M3A03

recall and demonstrate proficiency with multiplication facts for 3, 4, 5 and 10; extend and apply facts to develop the related division facts

6.09 Multiplication by 10

Ideas

Are you ready?

Examples

Example 1

Multiply numbers by 10

Examples

Example 2

Outcomes

AC9M3N04

AC9M3A03

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