Grade 6 Mathematics
PERCENT means "per 100" or "out of 100."
The symbol % came from writing "per 100" quickly!
50% means 50 out of 100, which equals 1/2 or 0.5
| Percent | Fraction | Decimal |
|---|---|---|
| 100% | 1/1 = 1 | 1.0 |
| 50% | 1/2 | 0.5 |
| 25% | 1/4 | 0.25 |
| 75% | 3/4 | 0.75 |
| 10% | 1/10 | 0.1 |
| 20% | 1/5 | 0.2 |
Percent to Decimal: Divide by 100 (move decimal LEFT 2 places)
45% = 45 / 100 = 0.45
Decimal to Percent: Multiply by 100 (move decimal RIGHT 2 places)
0.72 = 0.72 x 100 = 72%
Fraction to Percent: Divide numerator by denominator, then convert to percent
3/5 = 3 / 5 = 0.6 = 60%
Percent to Fraction: Write over 100, then simplify
40% = 40/100 = 2/5
Find 30% of 80
Convert percent to decimal: 30% = 0.30
Multiply: 0.30 x 80 = 24
Shortcut using benchmarks:
10% of 80 = 8 (just move decimal left once!)
30% = 3 x 10% = 3 x 8 = 24
WRONG: 0.45 as a percent = 0.45% (NO! This is way too small!)
RIGHT: 0.45 as a percent = 45% (Move decimal RIGHT 2 places)
Memory trick: Percent looks BIGGER than decimal, so when converting decimal to percent, the number gets BIGGER!
WRONG: 25% of 80 = 25 + 80 = 105
RIGHT: 25% of 80 = 0.25 x 80 = 20 (Convert percent to decimal, then MULTIPLY)
1. Convert to percent:
a) 0.35 = % b) 0.8 = % c) 0.05 = %
2. Convert to decimal:
a) 60% = b) 5% = c) 125% =
3. Convert fraction to percent:
a) 1/4 = % b) 3/5 = % c) 7/10 = %
4. Find the percent of each number:
a) 50% of 120 = b) 25% of 80 = c) 10% of 45 =
5. A video game costs $60. It's on sale for 20% off. How much is the discount?
Show work: 20% of $60 = x = $ discount