Numerical Ability · Editorial

Basic operations (Numerical)

Fractions, decimals, percent — no calculator discipline.

Practice this topicOpen flashcards
Checked
2026-08-13
Sources
1
Price
Free
  • 1,900+ original items
  • Prepaid · no auto-renew
  • Independent — not CSC
  • Built for mobile 4G

Basic-operations items cover the arithmetic you must do quickly without a calculator: fractions, decimals, percent, ratios, and order of operations. On CSE-PPT Numerical Ability, small slips (decimal place, percent vs. percentage points) cost easy points.

How to approach

  1. Rewrite before you compute. Convert mixed numbers, align decimals, or turn percent into fractions (/100).
  2. Estimate first. A rough range kills impossible options (e.g., 18% of ₱2,500 cannot be ₱2,000).
  3. Mind PEMDAS/MDAS. Parentheses and multiplication/division before addition/subtraction.
  4. Keep units and pesos tidy. Label partial answers so you don’t add ₱ to a bare count.
  5. Simplify fractions early. Cancel common factors before multiplying large numbers by hand.

Worked example

Stem: A flash sale takes 20% off a ₱1,450 jacket. How much does Ana pay if she also uses a ₱50 voucher after the discount?

  1. A.₱1,110
  2. B.₱1,160
  3. C.₱1,110.50
  4. D.₱1,400

Work: 20% of 1,450 = 0.20 × 1,450 = 290. Price after discount = 1,450 − 290 = 1,160. Then voucher: 1,160 − 50 = 1,110. Apply percent first, then the flat voucher (unless a stem says otherwise). Answer: A. ₱1,110.

Common traps

  • Percent of vs. percent more — Treating “20% more than 80” as 20% of 80 only.
  • Discount stacking order — Subtracting a voucher before the percent when the stem says after discount.
  • Decimal shift — 0.5 × 36 written as 1.8 instead of 18.
  • Fraction upside-down — Dividing by 2/3 as ×2/3 instead of ×3/2.
  • Calculator fantasy — Leaving an exact fraction half-simplified and mis-copying to the answer sheet.

Quick practice

  1. What is 3/4 of ₱960?
  1. A.₱620 B. ₱720 C. ₱740 D. ₱800

Answer: B — (3×960)/4 = 2,880/4 = 720.

  1. 0.6 + 0.15 × 4 = ?
  1. A.3.0 B. 1.2 C. 0.75 D. 2.4

Answer: B — Multiply first: 0.15×4=0.6; then 0.6+0.6=1.2.

Study with this product

  1. Take the free diagnostic to see if this topic is a weakness.
  2. Drill Basic operations in Practice, or follow Today’s plan for short timed sets.
  3. Sit a full mock when recommended so arithmetic speed holds under whole-exam pressure.

Honest facts

  • This guide is a study aid, not an official CSC reviewer and not a pass promise.
  • We never invent official CSC dates, fees, or room assignments.
  • Sample stems here are original practice items for skill-building, not leaked exam content.
  • Readiness Score is a product metric — not a CSC rating prediction.

Next up

More Numerical Ability

All guides →

Ready to apply this?

Guides teach the skill. The free diagnostic shows which topics still need drills — ~40 items, no signup.

Take the free diagnosticExam coverage
  • 1,900+ original items
  • Prepaid · no auto-renew
  • Independent — not CSC
  • Built for mobile 4G