**Decimal numbers are those that are less than a whole number.** In this the first of our difficult series of 11-plus Maths quizzes on decimal numbers you will get some practice in using decimals in real life situations. By the way, in real life you would not be required to give answers with as many decimal places as shown in these questions.

This quiz is a little tougher than the others, so be sure to read the questions carefully. Look at all the answers before choosing one. You may find it handy to have a pencil and paper next to you to jot down any calculations.

The more you can do these kind of calculations quickly in your head, the better prepared you'll be in everyday life. Having a solid grasp of numbers, measures and conversions will mean you're one step ahead of the rest when it comes to working out mathematical calculations.

1.

What is 123.4 centimetres in metres?

12.34 m

123.4 m

0.1234 m

1.234 m

There are 100 cm in 1 m, so in 123.4 cm there are 123.4 ÷ 100 = 1.234 m

2.

How many kilograms are there in 1,312.76 grams?

1.31276 kg

1,312.76 kg

131.276 kg

13.1276 kg

There are 1,000 g in 1 kg, so in 1,312.76 g there are 1,312.76 ÷ 1,000 = 1.31276 kg

3.

What was 123.345 multiplied by if the answer is 12,334.5?

1,000

100

10

10,000

The rule for multiplying by a whole number beginning with 1 and followed by one or more zeros, e.g. multiplying by 10, 100, 1,000, ... is as follows: When multiplying by such a number, move the decimal point to the right by the same number of zeros as in the number: 100 × 123.345 = 12,334.5: the decimal point has moved two places to the right = the number of zeros in one hundred

4.

If you travel along the A1, the distance from London to Lincoln is 227.65 kilometres. What is this distance in metres?

22,706.50 m

227,650 m

2,276.50 m

22,765 m

There are 1000 m in 1 km, so in 227.65 km there are 227.65 × 1,000 = 227,650 m

5.

How many square centimetres are there in 5.5 square metres?

55,000 sq cm

5,050 sq cm

5,500 sq cm

550,000 sq cm

There are 100 cm in 1 m, so in 1 sq m there are 100 × 100 = 10,000 sq cm. In 5.5 sq m there are 5.5 × 10,000 = 55,000 sq cm

6.

How many grams are there in 7.4 kilograms?

70,004 g

74,000g

704,000 g

7,400 g

There are 1,000 g in 1 kg, so in 7.4 kg there are 1000 × 7.4 = 7,400 g

7.

What was 123.345 divided by if the answer is 0.123345?

10

100

1,000

10,000

The rule for dividing by a whole number beginning with 1 and followed by one or more zeros, e.g. dividing by 10, 100, 1,000, ... is as follows: When dividing by such a number, move the decimal point to the left by the same number of zeros as in the number: 123.345 ÷ 1,000 = 0.123345: the decimal point has moved three places to the left = the number of zeros in one thousand

8.

A certain object weighs 82,340.5 grams. What is this in kilograms?

8,234.05 kg

8.23405 kg

823.405 kg

82.3405 kg

There are 1,000 g in 1 kg, so in 82,340.5 g there are 82,340.5 ÷ 1,000 = 82.3405 kg

9.

What does 0.00001 have to be multiplied by to give 1?

100

10,000

100,000

1,000

For 0.00001 to become 1, the decimal point will have to move 5 places to the right. You will have to multiply 0.00001 by 100,000 - which has 5 zeros

10.

What is 50.60 metres in centimetres?

5,600 cm

50,060 cm

5,060 cm

506 cm

There are 100 cm in 1 m, so in 50.60 m there are 100 × 50.60 = 5,060 cm