FLU
Mental maths and numerical fluency
Arithmetic fast enough to quote from: multiplication, fractions, percentages and estimation under a clock.
- 1
Speed and technique
The handful of methods that survive time pressure, and the tables worth committing to memory.
- 1.1Arithmetic that survives a clockFree10 min
- 2
Estimation and bounding
Fermi decomposition, order-of-magnitude checks, and turning an estimate into an interval you would trade.