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Find the following sums or differences.

  • Align the terms at their decimal points.

  • Add each column, starting at the right. Since , carry a 1 to the next column.


  1. Set up the problem by aligning the decimal points. Unlike in part (a), you will do subtraction for each column.

    Notice that , so you will need to ''borrow'' from the columns to the left. So a tenth was “borrowed” from 8.0 so that 4 would be subtracted from 12 instead of 2. That meant the 0.6 would be subtracted from 7.9.

  2. Use parts (a) and (b) for help.

  3. Follow the steps from part (a). Remember that since , you will need to carry a to the next column