# Dividing Decimals by Whole Numbers. In long division, we use both multiplication and division.

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Dividing Decimals by Whole Numbers

In long division, we use both multiplication and division.

Remember our key Vocabulary…

) dividenddivisor quotient Parts of a division problem… GOES INTO DIVIDED BY

dividend divisor = quotient Parts of a division problem… dividend ÷ divisor= quotient

factor x factor = product Parts of a multiplication problem…

To keep your long division steps in order, remember the basic family… DAD –Divide the divisor into the dividend MOM –Multiply the divisor by the factor you are about to put into your quotient SISTER –Subtract the product from the dividend/difference BROTHER –Bring down the next digit in your problem ROVER –Repeat!

36 ÷ 9 36 9 Different Ways to Present the Same Problem 36 divided by 9 9 ) 36 9 divided into 36 “Divided by” means that the first number is the dividend and the second number is the divisor. “Divided into” means that the first number is the divisor and the second number is the dividend.

Writing the Division Problem… When you are thinking about lunch… I mean long division… think of In-and-Out.

Setting up your long division problem… ) 24 24 ÷ 9 9 IN – n- OUT INOUT

) 249 Does 9 go into 24? Yes. 2 times. Put the 2 over the 4 (my last underlined number) 2 9 x 2 = 18 Subtract 24-18 -18 6

) 249 2 -18 6 Going forward, we will not leave remainders when we divide anymore. Now you need to add a decimal point to the end of the dividend and add a zero..0 0 Bring the decimal point up into your answer.

) 249 2 -18 6.0 0 Does 9 go into 60? How many times? 9 x 6 = 54 6 -54 60 – 54 = 6 6

) 249 2 -18 6.0 0 6 -54 6 0 0 6 6 Repeat the same steps…

) 249 2 -18 6.0 0 6 -54 6 0 0 6 6 I see that if I go one more place, I will add another 6 to my quotient. Do you see this repeating pattern?

) 249 2.0 6 0 6 I can see that the six will keep repeating itself. I am, therefore, going to round my answer to the hundredths place… 2.666 = 2.67 66666

How do I know where to round my answer to? If you are doing a problem from the book or on a test then read the directions for the answer to that question. If you are in a grocery store trying to figure out something that will cost money, round to the pennies place. (hundredths) If you see “round to the nearest whole number” or “round to the nearest dollar,” then round to the ones place. If your answer stops in the thousandths place, do not round your answer. Leave it as it is!

What do I do if I have zeroes in my problem?

) 1402.527 Does 7 go into 14? Yes. 2 times. Put the 2 over the 4 (my last underlined number) 2 7 x 2 = 14 -14 0 Subtract 14-14= 0

) 1402.527 Does 7 go into 0 or 00? No. Put the 0 in the quotient over the 0 in the dividend. 2 7 x 0 = 0 -14 0 Bring down the zero 0 0 0 0 0 – 0 = 0

) 1402.527 Does 7 go into 2? No. Put the 0 in the quotient over the 2. 2 7 x 0 = 0 -14 0 Bring down the 2 0 0 0 02 0 2 – 0 = 2 0 2

) 1402.527 2 -14 00 0 0 0 2 0 0 2 Send up the decimal point.

) 1402.527 Yes. 7 x 3 = 21. Put the 3 in the quotient over the 5. 2 7 x 3 = 21 -14 0 Bring down the 5 0 0 0 0 2 0 25 – 21 = 4 0 2 Does 7 go into 25? 5 21 4 3

) 1402.527 Yes. 7 x 6 = 42. Put the 6 in the quotient over the 2. 2 7 x 6 = 42 -14 0 Bring down the 2 0 0 0 0 2 0 42 – 42 = 0 0 25 Does 7 go into 42? 2 42 4 63 21 0

) 1402.527 20063 And the answer is…

Let’s Practice…

) 12.9063 4.302

) 5185 103.6

) 108.546 18.09

) 1661.8811 151.08

) 1370.62222 62.301

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