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

# Decimal Numbers (Difficult)

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.
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
2.
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 digits will have to move 5 places to the left. You will have to multiply 0.00001 by 100,000 - which has 5 zeros
3.
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 digits to the right by the same number of zeros as in the number: 123.345 ÷ 1,000 = 0.123345: the digits have moved three places to the right = the number of zeros in one thousand
4.
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
5.
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
6.
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 digits to the left by the same number of zeros as in the number: 100 × 123.345 = 12,334.5: the digits have moved two places to the left = the number of zeros in one hundred
7.
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
8.
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
9.
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
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
Author:  Frank Evans 