Henry bought a book for $10.84, and the sales tax was 8.25%. How much sales tax did Henry pay on the book?

So here we know the base ($10.84) and we know the rate (8.25%) so we need to find the portion. Portion = base * rate.

So convert the percent to a decimal: 0.0825

Multiply it by the base: 0.8943

Simplify it to the nearest percent which would be the nearest hundreth: $0.89