Unit 5 Review Flashcards

ALA: Pre-AlgebraUnit 5 Percentages

What is...

100% of 80?

In your head:

X + X100% is the WHOLE THING:

100% of 80 is 80

What is...

200% of 80?

In your head:

X + X200% is the twice the whole:

200% of 80 is 160

What is...

50% of 80?

In your head:

X + X50% is half:

50% of 80 is 40

What is...

25% of 80?

In your head:

X + X25% is one-fourth:

25% of 80 is 20

What is...

10% of 80?

In your head:

X + X10% is one-tenth, so move the decimal one spot to the left:

10% of 80 is 8

What is...

20% of 80?

In your head:

X + X20% is twice as much as 10%:

20% of 80 is 16

What is...

15% of 80?

In your head:

X + X15% is halfway between 10% and 20%:

15% of 80 is 12

X + XThe meal cost $12.00 What is a 20% tip?

X + XThe meal cost $12.00

10% of $12.00 is $1.20. Double that to get 20%, so the tip would be $2.40.

X + XThe meal cost $25.00 A coupon gives you 20% off. How much will you pay?

X + X10% of 25 is $2.50. So 20% of 25 is double that, or $5. You’ll save $5, so you’ll pay $20.

10 is 50% of what number?

One way: 50% means half. 10 is half of 20.

Another way: Set up a proportion 50 = 10 50x = 1000, so x = 20. 100 x

Another way: set up an equation10 = 50% of x 10 = .5x x = 10/.5 = 20

10 is what percent of 50?

X + X

One way: set up a proportion

x = 10 100 50

50x = 1000, so x = 20. 10 is 20% of 50.

Another way: equation10 = x 50 so x = .2, which is 20%

What is 40% of 150?

In your head: 10% of 150 is 15. 40% is 4 times that much, or

4 x 15 = 60.

Another way: proportion 40 = x 100x = 6000 so x = 60. 100 150

Another way: equation40% of 150 = x, so .4(150) = x, so x = 60.

X + X1.3% of children are allergic to peanuts. In a pediatric hospital with 2000 patients a year, how

many would you expect to have peanut allergies?

X + XYou could set up a proportion:

1.3 = x 100 2000100x = 2600, so x = 26 kids allergic to peanuts.

30% of Americans have hay fever. Of those, 75% find over-the-counter

allergy medications helpful. How many people in a town of 1200

would have hay fever that was NOT helped by over-the-counter

medication?

X + X30% of 1200 is 360 people with hay fever. 75% of these 360, or ¾ of them, ARE helped by over-the-counter meds. That’s 270 who ARE helped by the medicine. That leaves 360 – 270, or 90 people, who are NOT helped.

Change the percent to a decimal and a fraction:

43%

Change the percent to a decimal and a fraction:

43% = .43 = 43 100

Change the percent to a decimal and a fraction:

135%

Change the percent to a decimal and a fraction:

135% = 1.35 = 135 = 27 100 20

Change the percent to a decimal and a fraction:

.6%

Change the percent to a decimal and a fraction:

.6% = .006 = 6 = 3 1000 500

Change the decimal to a fraction and a percent:

.6

Change the decimal to a fraction and a percent:

.6 = 6 = 3 = 60% 10 5

Change the decimal to a fraction and a percent:

.07

Change the decimal to a fraction and a percent:

.07 = 7 = 7% 100

Change the fraction to a decimal and a percent:

38

Change the fraction to a decimal and a percent:

3 = .375 = 37.5%8

You are done with the ALA Unit 5 Review

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Resources:

Picture on slides 2, 4, 6, 8, 12, 14, 16, 18Thinking Man by منتصف is licensed under CC BY-SA 4.0 خالد

Picture on slide 16 and 17Pasta salad closeup by Brynn is licensed under CC BY-SA 3.0

Picture on slide 18 and 19Som tam thai by Takeaway is licensed under CC BY-SA 3.0

Picture on slides 26 and 27No Peanuts Allergy Alert Pendant by BeInspiredDesigns is licensed under CC BY-NC 2.0; Cropped from original work.