Multiplication and division help make maths faster and smarter. In 11 Plus Maths, they are used to simplify problems, spot patterns, and test logical thinking skills.
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Multiplying by 1?8 is the same as dividing by 8 ? 64 ÷ 8 = 8. In general, multiplying by 1 over a number is the same as dividing by that number: in this case, 8
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To divide by a fraction, invert (turn upside down) the fraction and multiply. LEARN this technique. So, 12 ÷ 2?7 = 12 × 7?2 = (12 × 7) ÷ 2 = 84 ÷ 2 = 42
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Short cut: 17 × 25 = (17 × 100) ÷ 4 = 1,700 ÷ 4 = 425. Multiply 25 by 4, then divide the product by 4. Be on the LOOKOUT for products that can be simplified: this will enable you to do the calculation in your head
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1?5 × 25 = 25 ÷ 5 = 5. In general, multiplying by 1 over a number is the same as dividing by that number: in this case, 5
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10,000 × 25 = 250,000. To multiply 25 by 1,000, just add three zeros to 25. If there is a decimal point in the number, move the decimal point 3 places to the right and add a zero for each place position if there are no digits in those place positions. You should be able to do this in your head
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49 × 13 = (50 × 13) - 13 = 637. Increase 49 by 1 and do the multiplication THEN subtract 13. Be on the LOOKOUT for products that can be simplified: this will enable you to do the calculation in your head
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50 ÷ 2?100 = 50 ÷ 1?50 = 50 × 50 = 2,500. To divide by a fraction, invert (turn upside down) the fraction and multiply, but DON'T forget to simplify the fraction whenever you can. LEARN this technique
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The number of 1?9 in 50 = 50 × 9 = 450. To divide by a fraction, invert (turn upside down) the fraction and multiply: in this case, dividing by one ninth is the same as multiplying by 9. LEARN this technique
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12 ÷ 7 = 1 remainder 5. You are dividing by 7, so the fractional remainder must be 5?7
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18 ÷ 5 = 3 remainder 3. You are dividing by 5, so the fractional remainder must be 3?5
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