Welcome to the third in our series of Very Easy Eleven Plus maths quizzes on Multiplication and Division. These can be testing at times – especially when dealing with large numbers. They often require pencils and paper for you to do your calculations but, you’ll be happy to hear, there are some simple ways to work many of them out.
Here’s an example: if you are asked to multiply a number by 95, then all you have to do is multiply it by 100, then multiply it by 5, and finally subtract the smaller number from the larger one:
8 x 95 = (8 x 100) - (8 x 5) = 800 - 40 = 760
See how easy it is when you can simplify the calculation. Read the helpful comments after each question for more tips which will help you revise for your exams. Good luck!
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To quickly divide by 5, first divide by 10 then double your answer:
425 ÷ 10 = 42.5, then 42.5 x 2 = 85
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To divide by 200, first divide by 100 by moving the decimal point 2 places to the left, then divide by 2:
1,080 ÷ 100 = 10.8, then 10.8 ÷ 2 = 5.4 |
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To multiply by 40, first multiply by 4 then by 10:
12 x 4 = 48, then 48 x 10 = 480
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'Double' means multiply by 2, and ‘squared’ means multiplied by itself:
6 x 2 = 12, then 12 x 12 = 144 |
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‘Cubed’ means multiplied by itself twice, just like finding the volume of a cube: vol = b x h x w.
3 x 3 x 3 = 27 |
To multiply by 2,000, simply multiply by 2 then by 1,000 by adding 3 zeros:
2 x 7.5 = 15, then 15 x 1,000 = 15,000 |
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‘Quartered’ means divided by 4: 64 ÷ 4 = 16
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To multiply by 300, first multiply by three, then by 100:
90 x 3 = 270, then 270 x 100 = 27,000. Alternatively, if both numbers end with zeroes, these can be removed and added again at the end:
9 x 3 = 27. We removed 3 zeros, so we add them again to get 27,000 |
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To quickly divide by 3,000, first divide by 1,000, then divide your answer by 3:
57,000 ÷ 1,000 = 57, then 57 ÷ 3 = 19
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A quick way to multiply by 101 is to first multiply by 100, then add the original number:
93 x 100 = 9,300, then 9,300 + 93 = 9,393
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