PSHS NCE Percent Reviewer

TEACHER ABI PSHS NCE · QUANTITATIVE ABILITY

Percent

Turn fractions and decimals into percents, find a percent of a number, and solve simple increase, decrease, discount, and score problems.

Grade 6–7 friendlyFast percent tricksRegular practiceQuick Fire + Mastery

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Percent

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Percent means “out of 100”

25% = 25/100 = 1/4 = 0.25

These all describe the same amount.

Useful percent facts to know:
50% = half
25% = one fourth
75% = three fourths
10% = divide by 10
1% = divide by 100

DO IT FAST

Use FRIENDLY PERCENTS first

1. 10%: Move the decimal point one place left.
2. 5%: Find 10%, then take half.
3. 20%: Find 10%, then double it.
4. 25%: Find one fourth.
5. 50%: Find half.
6. Other percents: Convert to a decimal or fraction when that is easier.

WORKED EXAMPLES

Six patterns you should recognize

1. Fraction to percent

3/4 = ?%

3 ÷ 4 = 0.75 = 75%

75%

2. Decimal to percent

0.36 = ?%

0.36 × 100 = 36%

36%

3. Find a percent of a number

What is 20% of 80?

10% of 80 is 8. Double it.

16

4. Find the whole

15 is 25% of what number?

25% is one fourth. If one fourth is 15, the whole is 15 × 4.

60

5. Discount

A ₱500 item is 20% off.

20% of ₱500 = ₱100.

₱500 − ₱100 = ₱400

Sale price: ₱400

6. Percent score

A student got 18 out of 20 correct.

18/20 = 0.9 = 90%

90%

TRY WITH ME

Find 15% without a long formula

What is 15% of 200?

1. 10% of 200 = 20.
2. 5% is half of 10%, so 5% of 200 = 10.
3. 15% = 10% + 5%.

30

COMMON TRAPS

Watch out for these

Forgetting percent means out of 100.
35% = 35/100 = 0.35.

Finding the discount but not the sale price.
If the question asks what you pay, subtract the discount.

Moving the decimal the wrong way.
Decimal to percent: multiply by 100.

Using a long method when a friendly percent works.
For 25%, 50%, 10%, and 5%, mental math is often faster.

REGULAR PRACTICE

Build the skill

These mix conversions, percent of a number, finding the whole, discounts, and test scores.

QUICK FIRE

Can you see the friendly percent?

Five short questions. Use mental math whenever possible.

Question 1 of 5

FRESH MASTERY CHECK

Can you do it without hints?

Score 5/5 to verify this competency. If you miss one, a fresh set will be ready.

NEED HELP?

Percent problems still slowing you down?

Send Teacher Abi the question that confused you and your result. I can help you find the shortest valid method.

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