How can I work out new number facts?

How can number facts help me find an answer?

What are number facts?

Number facts are simple calculations with two numbers. They could be addition, subtraction, multiplication or division. Sometimes these can be called fact families.

Number bonds (like 3 + 7 = 10, or 9 - 4 = 5) or facts learned from times tables (like 4 x 6 = 24 or 27 ÷ 3 = 9) are number facts.

How can number facts help you find new answers?

It is good to learn number facts so you can use them quickly. This can really help when you've got a more difficult problem.

Sometimes maths problems aren't just about adding or subtracting or multiplying or dividing. Sometimes you need to do more than one of these to get the answer.

When you have to do this it is good to remember

subtracting is the opposite of adding

dividing is the opposite of multiplying

Remembering your number facts will help you do these calculations quickly so there will be less chance of getting lost or mixed up.

Example

If three pizzas cost £15 how much will four cost?

To work out how much four pizzas cost it would help to know what one costs. We don't know that yet but we can work it out.

Three pizzas cost £15 so we can use a division number fact to work out the cost of one.

£15 ÷ 3 = £5

Now we know that one pizza costs £5 we can use a multiplication number fact to work out the cost of four.

4 x £5 = £20

Well done. You've just used number facts to find the answer.