Answer:
To find a 20 percent tip quickly, first find 10%, and then multiply it by 2.
Step-by-step explanation:
To find 10%, move the decimal 1 place to the left. So 10% of 53.82 is 5.382. Let's round that to 5.4 to simplify. Multiply it by 2 to get to 20% which is 10.8 and round to the nearest dollar to make $11.