WEBVTT
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Part a) Calculate 7848 divided by 12.
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There is a second part of this question that we will look at later.
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One way of working out this division calculation is using the bus stop method.
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In order to do this, we need to know our 12 times table.
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We cannot divide seven by 12.
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Therefore, we need to carry the seven to the hundreds column.
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78 divided by 12 is equal to six remainder six.
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This is because six multiplied by 12 is equal to 72.
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And the difference between 72 and 78 is six.
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We put a six on the answer line.
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And we carry the remainder.
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64 divided by 12 is equal to five remainder four.
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This is because five multiplied by 12 is equal to 60.
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And the difference between 60 and 64 is four.
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We put a five on the answer line and once again carry the remainder, in this case four.
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48 divided by 12 is equal to four as four multiplied by 12 equals 48.
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This means that our final answer is 654.
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7848 divided by 12 equals 654.
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We can check this answer by multiplying 654 by 12 as multiplication is the inverse or opposite of division.
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In order to do this, it is worth splitting 654 into three parts.
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We will multiply 600 by 12, 50 by 12, and four by 12.
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As six multiplied by 12 is equal to 72, 600 multiplied by 12 is equal to 7200.
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We add the two zeros.
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Five multiplied by 12 is equal to 60.
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Therefore, 50 multiplied by 12 equals 600.
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Finally, four multiplied by 12 equals 48.
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Adding the units column gives us eight.
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Adding the tens column gives us four.
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Adding the hundreds columns, two plus six, gives us eight.
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And the only number in the thousands column is seven.
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Therefore, 654 multiplied by 12 is 7848.
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This means that our answer was correct.
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The second part of the question said the following. b) Calculate nine-quarters minus three elevenths.
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Give your answer as a mixed number.
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In order to add or subtract any two fractions, we need to find a common denominator.
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One way of doing this is to find the lowest common multiple of the two denominators, in this case four and 11.
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The lowest common multiple of four and 11 is 44 as this is the lowest number in both of four and 11 times tables.
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To get 44, we need to multiply the first denominator by 11.
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We need to multiply the denominator of the second fraction by four.
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Remember with fractions, whatever we do to the bottom, we must do to the top.
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If we’re multiplying the denominator by 11, we have to multiply the numerator by 11.
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Four multiplied by 11 is 44.
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And nine multiplied by 11 is equal to 99.
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With our second fraction, 11 multiplied by four is equal to 44.
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On the top, three multiplied by four is equal to 12.
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Once the denominators are the same, we just need to subtract the two numerators.
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The denominator stays as 44.
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99 minus 12 is equal to 87.
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We could do this using column subtraction if needed.
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Nine minus two is equal to seven.
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And nine minus one is equal to eight.
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Therefore, 99 minus 12 equals 87.
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We have therefore calculated that nine-quarters minus three elevenths is equal to eighty-seven forty-fourths or 87 over 44.
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This is not the end of the question though as we were asked to give our answer as a mixed number.
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In order to do this, we need to work out how many 44s go into 87.
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Well, two multiplied by 44 is equal to 88, which is too big.
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This means that we we’ll have one whole one as only one 44 goes into 87.
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We have a remainder of 43 as 87 minus 44 is equal to 43.
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This means that the answer to nine-quarters minus three elevenths as a mixed number is one and 43 over 44.