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.
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There are 100 cm in 1 m, so in 50.60 m there are 100 × 50.60 = 5,060 cm
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There are 1,000 g in 1 kg, so in 7.4 kg there are 1000 × 7.4 = 7,400 g
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There are 100 cm in 1 m, so in 123.4 cm there are 123.4 ÷ 100 = 1.234 m
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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
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There are 1,000 g in 1 kg, so in 1,312.76 g there are 1,312.76 ÷ 1,000 = 1.31276 kg
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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
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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
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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
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There are 1000 m in 1 km, so in 227.65 km there are 227.65 × 1,000 = 227,650 m
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There are 1,000 g in 1 kg, so in 82,340.5 g there are 82,340.5 ÷ 1,000 = 82.3405 kg
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