# maths

maths

## numbers

Any  number above zero is a positive number. Positive numbers are written with no sign or a '+' sign in front of them and they are counted from zero to the right.

1 of 7

## number

Any number below zero is a negative number. Negative numbers are always written with a '-' sign in front of them and they are counted from zero to the left.

2 of 7

## number

Always look at the sign in front of a number to see if it is positive or negative.

Positive numbers get higher the further we move right, so 5 is more than 2.

Negative numbers get lower the further we move left, so -5 is less than -2.

3 of 7

## numbers

If you get 7 out of 10 in a test, you can write your score as 7/10.

7 expressed as a fraction of 10 is 7/10.

Similarly, if there are 20 socks in a drawer and 4 of them are blue, 4/20 of the socks are blue.

So, 4 expressed as a fraction of 20 is 4/20. We can put this into its simplest form by dividing the top and bottom numbers by 4. So we get 1/5.

4 of 7

## maths

If you are expressing a number as a fraction of a second, the first number goes on the top and the second number on the bottom.

5 of 7

We use a decimal point to separate units from parts of a whole (like tenths, hundredths, thousandths, etc).

• 0.1 is a tenth, 1/10 of a unit
• 0.01 is a hundredth, 1/100 of a unit
• 0.001 is a thousandth. 1/1000 of a unit
6 of 7

## math

To multiply 237 by 4 without using a calculator, you can set it out like this:

1. Start with 4 × 7, which is 28, so write the 8 and carry the 2 to the tens column.

2. 4 × 3 = 12, but remember to add the carried 2 to get 14. Write the 4 and carry the 1 to the hundreds column.

3. 4 × 2 = 8, and we add the carried 1 to get 9.

Therefore 237 × 4 = 948

This method is called short multiplication.

7 of 7