Random, but see, for me, on $27.45 (assume post-tax, I don’t usually worry about pre-tax), to simplify the math, I’d say “27 x 2 = 54, move the decimal, 5.4, round up for the nearest dollar, $5.55". And conveniently, 27.45 * 0.2 = 5.49, so I’m good. (when it starts getting over the 50 cent mark, I round up on the…