# Simple algebra*

In the midst of grading exams now. One problem consists of computing determinants and many students give the answer $(1+a)^3 -3a -1$ without simplifying it to $a^3+3a^2$. I have this nagging suspicion that they are not really able to expand a simple cubic. I wonder if this batch are those who at Primary 5 and 6, had algebra stripped out of their syllabus and replaced with some ghastly model building or what-you-call-it process.

*nothing to do with proper sub-algebras.

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