Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. 4.4 Dividing Decimals

22 © 2012 Pearson Prentice Hall. All rights reserved Dividing Decimals Dividing decimal numbers is similar to dividing whole numbers. The only difference is that we place a decimal point in the quotient. Dividing by a Whole Number Step 1: Place the decimal point in the quotient directly above the decimal point in the dividend. Step 2: Divide as with whole numbers.

33 © 2012 Pearson Prentice Hall. All rights reserved Dividing Decimals Dividing by a Whole NumberExample Step 1 : Place the decimal point in the quotient directly above the decimal point in the dividend. Step 2: Divide as with whole numbers. 5.9

44 © 2012 Pearson Prentice Hall. All rights reserved Example Divide: 219.2÷8. divisor dividend quotient Check:

55 © 2012 Pearson Prentice Hall. All rights reserved Example Divide: 0.6÷4. divisor dividend quotient Check:

66 © 2012 Pearson Prentice Hall. All rights reserved Dividing by a Decimals If the divisor is not a whole number, before we divide we need to move the decimal point to the right until the divisor is a whole number.

77 © 2012 Pearson Prentice Hall. All rights reserved Example Divide: 6.888÷2.8. becomes 2.46

88 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. Divide ÷ 2.8 Estimating When Dividing Decimals ExactEstimate rounds to This is a reasonable answer.

99 © 2012 Pearson Prentice Hall. All rights reserved Estimating When Dividing Decimals Example: Divide: 0.54÷12. Then estimate to whether the proposed result is reasonable. Exact Estimate The estimate is 0.05, so is reasonable.

10 © 2012 Pearson Prentice Hall. All rights reserved Dividing by Powers Dividing Decimals by Powers of 10 such as 10, 100 or 1000 Move the decimal point of the dividend to the left the same number of places there are zeros in the power of 10.

11 Copyright © 2012 Pearson Education, Inc. Publishing as Prentice Hall. There are patterns that occur when dividing by powers of 10, such as 10, 100, 1000, and so on. The decimal point moved 1 place to the left. 1 zero 3 zeros The decimal point moved 3 places to the left. The pattern suggests the following rule  ,.  Dividing Decimals by Powers of 10

12 © 2012 Pearson Prentice Hall. All rights reserved Example Divide. a. b. = Move the decimal point 3 places to the left. = Move the decimal point 1 place to the left.