CPM Homework Help : MC1 Problem 9-107

Autumn and her friends had dinner at their favorite restaurant, and the bill came to $60. They decided to leave 18% of the bill for a tip. Without using a calculator, help them compute how much money is 18% of the bill.

Hint:

$10\%$ of $$60$ is $$6$
$5\%$ of $$60$ is $$3$
$1\%$ of $$60$ is $$0.60$
Can you combine these to find $18\%$ of $$60$ ? Can you find more than one way?

More Help:

You can see $18\%$ as $10\% + 5\% + 3\left(1\%\right)$ or as $2\left(10\%\right) − 2\left(1\%\right)$ .