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Published byScarlett Chapman Modified over 8 years ago

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Decimal Division You must learn the rules

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Dividing a decimal by a whole number 1.2 ÷ 2 Divisor = 2 Dividend = 1.2 Step 1: move the decimal in the dividend STRAIGHT up Divide as with whole numbers Check your answer by multiplying Quotient (0.6) x divisor (2) = dividend (1.2)

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Dividing by a Decimal 12 ÷ 0.6 The divisor ALWAYS has to be a whole number You make the divisor a whole number by moving the decimal point left to right IMPORTANT: when you move the decimal in the divisor, you must also move the decimal the same number of places in the dividend 12 ÷ 0.6. 12.0. ÷ 0.6.

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12 ÷ 0.6 continued We now have 120 ÷ 6 Divide as usual » 120 ÷ 6 = 20 Perform the inverse operation using the original problem » 0.6 x 20 = 6 x 20 = 120 Moving the decimal, 12.0. gives an answer of 12, one of the original factors.

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Let’s try another one 1.2 ÷ 0.2 Because the divisor is a decimal, we move the decimal point to make it a whole number Moving the decimal 1 place, 0.2 becomes 2 Remember: what we do in the divisor we must also do in the dividend Moving the decimal 1 place, 1.2 becomes 12 Divide as usual 12 ÷ 2 = 6 Going back to the original problems, 1.2 ÷ 0.2 Perform the inverse operation 0.2 x 6 = 1.2

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0.12 ÷ 0.6 0.6 is the divisor (outside) and 0.12 is the dividend (inside) Move the decimal 1 place to change the divisor 0.6 to the whole number 6 Move the decimal 1 place in 0.12 to make the dividend 1.2 We now have 1.2 ÷ 6 = 0.2 Check 0.2 x 0.6 = 0.12

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Important! The divisor always has to be a whole number but the dividend does not. The number of places you move the decimal point in the divisor is the number of places you move the decimal in the dividend.

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Let’s try another one 2 ÷ 0.42 ÷ 0.4 Which is the divisor? Which is the dividend? The decimal needs to be moved 1 place to make 0.4 = 4. Move the decimal in the dividend one place to make 2 = 20 Divide 20 ÷ 4 = 5 so the answer to 2 ÷ 0.4 = 5 Now check using inverse operations 0.4 x 5 = 4 x 5 = 20 and moving the decimal point one place = 2.0. divisor dividend

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Your turn! 25 ÷ 0.5 = Move the decimal in the divisor Move the decimal in the dividend Divide as usual Check using inverse operations And the answer is 50

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