There are three ways of looking at minus when teaching second grade math in the Waldorf school. There are (at least) three ways to look at a subtraction problem. (This is for the teacher to keep in mind; the students may not be fully conscious of this until 3rd grade.)

Using the example of 20 – 13:

*As a Take Away (or Subtraction) problem.* We take away 13 from 20.

*As a Difference Problem. We ask ourselves: “How far apart are 13 and 20?” or “How many steps are there going from 13 to 20?” *This will be especially clear to the students once they have moved it on the number line.

*As the Reverse of Addition*. We ask ourselves: “13 plus what is 20?”

The goal is to develop flexibility in the children’s thinking, so that sometimes they look at it as a *difference *problem, and sometimes as a *take away *problem, depending upon which approach is easier for a given problem.

The teacher should try to be consistent in the use of the words *“take away,” “difference,” “subtract” *etc. By saying “26 minus 14,” we leave it open for the children to solve the problem by either *taking away *or *finding the difference.*

The students should still be doing subtraction predominantly in the horizontal form (and in mental arithmetic) well into third grade and beyond.

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