Percents

What is percent?Percent (or per cent) means “per 100” or “out of 100”

For example:

If you answered 90 out of 100 questions correctly on a test you would receive 90 percent (or 90%)

That’s an A!

What is percent?What if your test only had 10 questions and you got 9 correct?

9 out of 10 or is equal to what percent?

You could set up a RATIO to find your score.

9 10

9 = ?10 100 Cross multiply

9 X 100 = 900 Then divide900 ÷ 10 = 90 or 90%

Try these 1 = ? 2 100

3 = ?5 100

Cross multiply 1 X 100 = ?Then divide? ÷ 2 = ? %

Cross multiply 3 X 100 = ?Then divide? ÷ 5 = ? %

2 = ?25 100

Cross multiply 2 X 100 = ?Then divide? ÷ 25 = ? %

Cross multiply 1 X 100 = 100Then divide100 ÷ 2 = 50 %

Cross multiply 3 X 100 = 300Then divide300 ÷ 5 = 60 %

Cross multiply 2 X 100 = 200Then divide200 ÷ 25 = 8 %

Now in reverseSuppose you are given a percentage and need to find the equivalent fraction (this happens in real life)

For example 10 percent of 20 is what?

This questions looks like this: 10 = ?100 20

Work your ratio Cross multiply 10 X 20 = 200 Then divide200 ÷ 100 = 2 or 2%

10 out of 100

of

Real life exampleYou are at a restaurant and need to leave a tip for the great service you received. It is normal to leave a tip of 20% for good service. Your bill was $40.

What should you leave as a tip?

20 percent of 40 is what?Work your ratio - Cross multiply 20 X 40 = 800 Then divide800 ÷ 100 = 8 or $8

20 = ?100 40

20 out of 100

of

You should leave a tip of $8

Try thisA jacket you want is 25% off. The regular price is $50. How much less will you have to pay?

What should you leave as a tip?

25 percent of 50 is what?Work your ratio - Cross multiply 25 X 50 = ? Then divide? ÷ 100 = ?

25 = ?100 50

20 out of 100

of

Did you getA jacket you want is 25% off. The regular price is $50. How much less will you have to pay?

What should you leave as a tip?

25 percent of 50 is what?Work your ratio - Cross multiply 25 X 50 = 1250Then divide1250 ÷ 100 = 12.50

25 = ?100 50

20 out of 100

of

Your jacket will cost $12.50 less$50 - $12.50 = $37.50

The EndPlease see the teacher for today’s

assignment