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Calculate 38.72 divided by 8.73, rounding your answer to the nearest tenth.
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First, we want to set up our division problem 38.72 is the dividend, 8.73 is the divisor.
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We don’t want our division problem to start with decimal values.
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So I take 8.73, move the decimal one, two places to the right.
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If I move the decimal place from 8.73 two places to the right, then I’ll need to move the decimal place from 38.72 two places to the right.
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Our new division problem will look like this: 873 divided by 3872.
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First, we asked, can 873 be divided into 387?
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No, it’s not possible.
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So we’ll have to divide 873 into 3872.
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Instead of just guessing random numbers, I want to use rounding here: 873 is almost 900.
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I want to think of something I can multiply 900 by that will equal about 3800.
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If I multiply 900 times four, it becomes 3600.
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I’m going to use this information to try to divide 873 into 3872 four times.
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In our dividing procedure, we multiply four by 873.
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Starting in the units place, four times three equals 12.
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Write down your two, carry your one.
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Moving on to the tens place, four times seven equals 28 plus one that we carried over equals 29.
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We write down our nine and carry our two.
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Next, we multiply four times eight which equals 32 and we add the two we carried over, 34.
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Now, we need to subtract.
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Two minus two equals zero.
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Moving to the left, we can’t take nine away from seven.
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So we need to borrow from the hundreds place.
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We’ll have a seven hundreds and now 17 tens.
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Then, we say 17 minus nine equals eight, seven minus four equals three, and three minus three equals zero.
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From here, we need to bring up our decimal place and add a zero in the tenths place, bring down the next digit, and then find out how many times 873 can be divided into 3800.
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Remember the first part of this problem we divided 873 into 3872.
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3800 is very close to 3872.
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We can use four again.
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We know that four times 873 equals 3492, which means we can copy that value again.
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From there, we need to subtract.
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We can’t subtract two from zero.
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So we need to borrow.
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But we can’t borrow from the 10.
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We’ll have to borrow from our eight.
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That leaves seven hundreds and 10 tens.
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We take one of those tens away, leaving us with nine tens and 10 ones.
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From there, 10 minus two equals eight, nine minus nine equals zero, seven minus four equals three, three minus three equals zero.
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At this point, you might be tempted to think we have the nearest tenth.
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But we have to remember that when we’re rounding to the nearest tenth, we have to look to the right of the tenths place — to the hundredths place.
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And that means we’ll need to do another round of division.
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So we add a zero to the hundredths place, bring down that zero.
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And then, we see we’re dealing with 3080 and we’ll need to go back to our estimating.
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We no longer need something about 3800.
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We now need to multiply 900 by something that’s close to 3000.
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We know 900 times three would be equal to 2700 and that’s pretty close.
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So we estimate that 873 will be divided into 3080 three times.
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And that means we need to multiply 873 by three.
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Three times three equals nine, seven times three equals 21.
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Write down our one, carry the two.
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Eight times three equals 24 plus two equals 26.
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We’ll go ahead and subtract one last time.
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We can’t subtract nine from zero.
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So we borrow from the eight, leaving us with seven.
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We bring the one over.
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10 minus nine equals one, seven minus one equals six.
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We can’t take six away from zero.
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We’ll borrow for our three, leaving us with two, carrying a one over.
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10 minus six equals four.
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And finally, two minus two equals zero.
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We could add another zero, bring it down, and divide again, over and over again.
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But we don’t have to because we’re trying to round this answer to the nearest tenth.
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We take the quotient we found 4.43, we look at the tenths place, and then we look to the right in the hundredths place, where there is a three.
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Three is less than five.
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Therefore, we round down.
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When we round down, the digit we’re rounding, in this place the four, stays the same.
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Everything to the left of the four, in this case just the units place, also stays the same.
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And everything to the right of what we’re rounding becomes a zero.
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4.40 in its simplest form is 4.4.
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When we divide 38.72 by 8.73 and round our answer to the nearest tenth, we get 4.4.