Multiplication and division by 0, 1, 10. Division of a number by itself.

Calculate each expression and compare its result with the number in the question.

Multiplying by 1 leaves a number unchanged, multiplying by 0 gives 0, and multiplying by 10 makes it ten times as large. Work out any division separately and compare its result too.

Read which operation is needed.

• Multiplying by 0 gives 0.
• Multiplying or dividing by 1 leaves the number unchanged.
• To multiply a positive whole number by 10, append a 0.

For example, 8 × 0 = 0, 8 × 1 = 8, 8 ÷ 1 = 8, and 8 × 10 = 80.

The ribbon is divided into 10 equal parts. Divide its whole length by 10 to find one part’s length.

Here the length is a multiple of ten: 70 ÷ 10 = 7. The answer is also in centimetres.

Any non-zero number divided by itself equals 1. The whole amount makes one group of that same size.

For example, 7 ÷ 7 = 1. Check: 1 × 7 = 7. This rule does not apply to 0 ÷ 0 because division by 0 is not possible.

Multiplying by 1 leaves the number unchanged. One group of that size has the starting number of objects.

For example, 24 × 1 = 24. Choose the starting number.

Any non-zero number divided by itself equals 1. The whole amount makes one group of that same size.

For example, 7 ÷ 7 = 1. Check: 1 × 7 = 7. This rule does not apply to 0 ÷ 0 because division by 0 is not possible.

Ten identical boxes contain ten times as many pencils as one box. Multiply the amount in one box by 10.

To multiply a positive whole number by 10, append a 0. For example, 6 × 10 = 60.

First read the operation sign and the second number.

• Multiplying by 0 gives 0.
• Multiplying or dividing by 1 leaves the number unchanged.
• To multiply a positive whole number by 10, append a 0.
• To divide a multiple of 10 by 10, remove its final 0.
• A non-zero number divided by itself gives 1.
• Division by 0 is not possible. For that case, choose the answer saying the operation is invalid.

Work from left to right: multiply by 10 first, then divide the result by 10.

These operations undo each other, bringing you back to the starting number. For example, 6 × 10 ÷ 10 = 60 ÷ 10 = 6.

Multiplying any number by 0 gives 0. Each group contributes no objects.

For example, 9 × 0 = 0. This differs from multiplying by 1, which leaves the number unchanged.