Decimal Numbers (Year 4)

In KS2 Maths children will come to understand decimal numbers. In Year Four children will learn the initial place value of figures in decimal numbers - tenths. They will also do some basic adding and subtracting with decimals and be introduced to rounding decimal numbers up or down.

Decimal numbers are numbers that are not whole. 3, 7, 9 and 10 are whole numbers. 3.4, 7.1, 9.2 and 10.3 are decimal numbers. Can you spot the difference? The decimal numbers have a 'dot' which is called a decimal point. Adding and subtracting decimal numbers is just like doing it with whole numbers, for example 11 + 12 = 23 and 1.1 + 1.2 = 2.3. Decimal numbers can also be changed into the whole number they are closest to. We call this rounding up or down. For example, 4.7 would be rounded up to 5 but 4.4 would be rounded down to 4.

Play this quiz and find out how good you are at adding, subtracting and rounding decimal numbers.