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Understanding long division

Оглавление

Long division allows you to divide larger numbers in a systematic way.

For example, to divide , set up the problem as follows:


Begin by trying to divide 6 into the first digit of 347 by itself. Because 3 is less than 6, this division doesn’t work. Next, try dividing 6 into 34. In this case, 6 goes into 34 as many as 5 times, so record this answer over the 4:


Now, multiply , placing this result below 34:


To complete this step, subtract and bring down the 7 next to this result:


At this point, you have a new number to try dividing 6 into: 6 goes into 47 no more than 7 times. Now, multiply :


To finish up the problem, subtract :


Thus, — that is, 57 with a remainder of 5.

As another example, suppose you want to divide . Set up the problem as follows:


To begin, note that you can divide 1,006 into 7,458 a maximum of 7 times. Thus, write 7 above the 8, multiply , then subtract and bring down the 5:


Now, you can divide 1,006 into 4,165 a maximum of 4 times. So write 4 above the line after the 7, multiply , then subtract and bring down the 3:


To finish the problem, you can divide 1,006 into 1,413 just 1 time. So this time, write 1 above the line after the 4, multiply , and subtract:


Therefore, — that is, 741 with a remainder of 407.

Basic Math & Pre-Algebra All-in-One For Dummies (+ Chapter Quizzes Online)

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