# July, 2013

## How the Mathematical Ninja squares brackets

"Yuk," said the student, faced with $(x+y+z)^2$. FOIL doesn't work." The Mathematical Ninja thought carefully before speaking: on the one hand, FOIL was a cheap tactic with a single use, but on the other, the student hadn't said $x^2 + y^2 + z^2$, which would have meant instant decapitation. "I