Adding and Subtracting with Mixed Numbers

Use one of the following strategies for adding or subtracting mixed numbers:

Example: 3  1/2  -  2   3/4

Strategy 1: Change the mixed numbers to improper fractions then
                       add or subtract.

                           Step 1: Change 3 1/2 to 7/2
                                       Change 2 3/4 to 11/4

                           Step 2: The new equation becomes : 7/2 - 11/4

                    Step 3: Find a common denominator:14/4 - 11/4

                    Step 4: Add or subtract:3/4

                    Step 5: Reduce if necessary: final answer = 3/4

   (Be careful ! This method can be more difficult if you are working with big numbers)
                                     

Strategy 2: Add or subtract the whole number parts and fraction parts
                       of the mixed numbers separately.

                   Step 1: Find a common denominator for the fraction parts
                              of the mixed number:  4

                   Step 2: Add or subtract the fraction parts:  2/4 - 3/4

                       Step 3: If you can't subtract, you will need to borrow from
                               the whole number part of the first mixed number.
                               In this case we will borrow from the 3 in 3 1/2.
                               Now we have: 2  6/4 - 2  3/4

               Step 4: Now we subtract the fractions: 6/4 - 3/4 = 3/4
                                          and the whole numbers: 2 - 2 = 0         
                                         to get: 0  3/4

               Step 5: Reduce if necessary.

                             The answer is 3/4

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