Subtraction Algorithms 7. Students often solve problems in ways that are different from instruction. Examine the algorithm a student used to compute 1,004 - 726. It is often referred to as the Partial Differences Algorithm. 1,004 - 726 . "First, I took away 700 so that leaves 304." . "Next, I took away 20, so I'm at 284." . "Last, I took away 6. The answer is 278." a) Model the Partial Differences Algorithm on the number line