The rounding up or down of numbers is a major part of KS2 Maths. In Years Three and Four children will be taught how to go about rounding whole numbers to the nearest ten or hundred.

Rounding numbers down or up involves reducing or increasing them to the nearest ten or hundred. When we round a number we say which is the nearest ten or hundred to that number. That's easy to do with most numbers, but what about ones that end in a 5 or a 50? Well, these are always rounded up rather than down.

Rounded numbers aren't exactly correct, but they are a good estimate and are especially useful when working with larger numbers. Take this quiz and find out what you know about rounding numbers up or down. For 7-9 year olds.

1.

What is the nearest 100 to 850?

700

800

900

1,000

As the number ends in 50 we always round up to the nearest 100

2.

Why is rounding 45 more difficult?

It is half way between 40 and 50

It is a multiple of 9

It is an odd number

It is half way between 0 and 50

As 45 is half way between 40 and 50 the rule is to always round 5 up

3.

In which of these questions would you need to round the answer up?

A box holds 6 cakes. How many boxes will I need to hold 34 cakes?

Tickets cost £5. I have £22 how many tickets can I buy?

Sweets cost 20p. I have £1. How many sweets can I buy?

A pencil is 10cm. How long will 3 pencils be?

34 ÷ 6 = 5 with 4 left over. As the remaining 4 need to go in a box 6 boxes are needed

4.

Which of these numbers would be rounded **down** to the nearest 100?

134

250

879

191

Just as 5 is rounded up to 10, 50 is rounded up to 100 so 250 would not be rounded down

5.

Which is the nearest 100 to 379?

100

200

300

400

379 is closer to 400 than to 300

6.

Which of these numbers would be rounded **down** to the nearest 10?

36

25

19

91

25 is rounded up as it ends in a 5

7.

Which is the nearest 10 to 75?

70

80

90

100

Remember that 5s are rounded up not down

8.

Which is the nearest 10 to 87?

80

90

100

200

87 is only 3 less than 90

9.

Which is the nearest 10 to 33?

10

20

30

40

33 is closer to 30 than 40

10.

What is the nearest 100 to 641?

600

700

800

1,000

As 41 is less than 50, 641 is rounded down to 600