# [Maths-Education] Subtraction

**Ian Thompson**
F.I.Thompson@ncl.ac.uk

*Mon, 10 Apr 2000 11:33:11 +0100 (BST)*

Judy Mousley wrote:
Many 'difference' problems can be solved by adding on. However, the
solution (while a missing addend) is actually the solution to a
subtraction equation. (I know that's academic, but think about how an
algebraic representation of the same sorts of problems would probably
be solved.)
The fact that we call them 'missing addend' problems, and write them 3 + []
= 7 (with an addition symbol) surely strengthens my argument! And to solve
it algebraically you would probably use 'inverse operations', just as you
might use addition to solve a subtraction, so I don't think that invoking
algebra clarifies the issue.
Ian
Ian Thompson
Department of Education,
University of Newcastle upon Tyne
St Thomas St
Newcastle upon Tyne
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U.K.
Tel. (+44) (0)191 222 6375
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