Civil Service Exam Review · Numerical Ability · Topic 1 · 1 of 4
Fractions, decimals and percents
Move between fractions, decimals and percents, and solve percent problems quickly.
Why this matters
Numerical ability items often hide a simple percent or fraction step inside a word problem. Converting quickly saves time for the harder items.
1. Converting
- Fraction to decimal: divide the numerator by the denominator. 3/8 = 3 ÷ 8 = 0.375.
- Decimal to percent: multiply by 100. 0.375 = 37.5%.
- Percent to fraction: write over 100 and simplify. 35% = 35/100 = 7/20.
2. The percent equation
Part = Rate × Base. Find whichever one is missing.
- 45% of 260: 0.45 × 260 = 117.
- What percent of 80 is 12? 12 ÷ 80 = 0.15 = 15%.
3. Percent change
Percent change = (new − old) ÷ old × 100. A price that rises from ₱800 to ₱920 rose by 120 ÷ 800 = 15%.
Exam tip
After a discount of d%, the price is (100 − d)% of the original. To undo it, divide: ₱1,350 after a 25% discount came from ₱1,350 ÷ 0.75 = ₱1,800.