Question

Estimate a 15% tip on a taxi ride that costs $23.25.

Answer 1

if you want to estimate in your head one way is to
first take 10 % (shift decimal to the left once)
$2.33 ---- this is 10%
then take 1/2 of that $1.17

add the two items to make 15%: $3.50

Answer 2

Medal? :)