Shitty Math Pro Tip: If you ever have to work with numbers larger than 10, convert it to scientific notation and then round to a single significant figure.

? = 0.04 x 75
? = (4 x 10^-2) x (7.5 x 10^1)
? ~= (4 x 10^-2) x (8 x 10^1)
? = 4 x 8 x 10^-1
? = 32 x 10^-1
? = 3.2
? ~= 3

See how easy that is? Here’s another one:

? = 12 x 12
? = (1.2 x 10^1) x (1.2 x 10^1)
? ~= (1 x 10^1) x (1 x 10^1)
? = 1 x 10^2
? = 100

Bam, lock it in.