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Chapter 3 Decimals Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc. 3.3 Adding and Subtracting Decimals Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc. Adding Decimals The addition of decimals is related to the addition of fractions. 3 4 7 10 10 10 0.3 0.4 0.7 Adding Decimals 1. 2. 3. Write the numbers to be added vertically and line up the decimal points. Extra zeros may be added to the right of the decimal points if needed. Add all the digits with the same place value, starting with the right column and moving to the left. Place the decimal point of the sum in line with the decimal points of the numbers added. Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc. Adding Decimals Example: Add 718.97 + 496.5. 718.97 + 496.5 0 1215.47 Write the numbers vertically and line up the decimal points. Add zeros where necessary for place holders. This value is the same as 1215 47 . 100 Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc. Subtracting Decimals The subtraction of decimals is related to the subtraction of fractions. 4 3 1 5 10 2 10 3 10 5.4 2.3 3.1 Subtracting Decimals 1. 2. 3. Write the numbers to be subtracted vertically and line up the decimal points. Additional zeros may be added to the right of the decimal point if not all numbers have the same number of decimal place. Subtract all the digits with the same place value, starting with the right column and moving to the left. Borrow when necessary. Place the decimal point of the difference in line with the decimal points of the two numbers being subtracted. Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc. Subtracting Decimals Example: Subtract 243.967 – 84.2. 1 13 13 243.967 – 84.200 159.767 Write the numbers vertically and line up the decimal points Add zeros where necessary for place holders. This value is the same as 159 767 . 1000 Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc. Subtracting Decimals Example: Subtract 8 – 1.623. 9 9 7 10 10 10 8. 000 – 1.623 6.377 Write the numbers vertically and line up the decimal points. Add zeros where necessary for place holders. This value is the same as 6 377 . 1000 Copyright © 2012, 2009, 2005, 2002 Pearson Education, Inc.