BECE Mathematics
Past Questions

AI Explanation

**The reasoning** To find 25% of 240, convert the percentage to a fraction or decimal, then multiply: 25% = 25/100 = 1/4 (or 0.25) So: 25% of 240 = 1/4 × 240 = 240 ÷ 4 = **60** Quick mental trick: 25% is always "one quarter" of any number. Just divide by 4! **Why the wrong options tempt you** - **Option A (30)**: You might have calculated 25% of 120 instead of 240, or divided by 8 instead of 4. - **Option B (40)**: This is 10% of 400, not 25% of 240 — you probably mixed up the numbers or your percentage. - **Option D (80)**: This looks like you found 1/3 of 240 instead of 1/4. Easy slip when rushing! **Quick takeaway** Remember: **25% = quarter it** (divide by 4). For JAMB Maths, mastering percentage-to-fraction conversions (25%=1/4, 50%=1/2, 10%=1/10) saves you precious time and eliminates silly mistakes!

AI Explanation

**The reasoning** To convert a fraction to a percentage, multiply by 100%. **7/10 × 100% = 700/10 = 70%** Think of it this way: "percent" means "per hundred" (from Latin *per centum*). You're asking "out of 100 parts, how many?" Since 7/10 means 7 out of 10 parts, scaling up to 100 parts gives you 70 out of 100 — which is 70%. **Why the wrong options tempt you** - **0.7%** — You converted to decimal (0.7) but forgot the ×100 step. A decimal and a percentage are NOT the same thing! - **7%** — You just slapped a % sign on the numerator. That's like saying 7 out of 10 is the same as 7 out of 100 — clearly wrong. - **100%** — That would mean the whole thing (10/10), not 7/10. **Quick takeaway** Fraction → Percentage? **Multiply by 100.** Decimal → Percentage? **Also multiply by 100.** The percentage is always bigger-looking than the decimal because you're scaling to "out of 100."

AI Explanation

**The reasoning** To convert a fraction to a percentage, multiply by 100%. 7/10 × 100% = (7 × 100)/10 % = 700/10 % = **70%** Think of it this way: "percent" means "per hundred" or "out of 100." So we're asking: "If 7/10 is our value, how many out of 100 is that?" Since 10 goes into 100 exactly 10 times, we multiply both top and bottom by 10: 7/10 = 70/100 = 70%. **Why the wrong options tempt you** - **Option A (0.7%)**: This happens if you convert to a decimal (0.7) but forget to multiply by 100. The decimal form is NOT the percentage. - **Option B (7%)**: You just took the numerator and slapped a % sign on it, ignoring the denominator entirely. - **Option D (100%)**: This would mean the whole thing (10/10), not 7/10. **Quick takeaway** Fraction to percentage? Multiply by 100%. Decimal to percentage? Also multiply by 100%. The % sign means you've already done that multiplication!

AI Explanation

**The reasoning** A square has **4 equal sides**. When you find the perimeter, you're measuring the total distance around the shape — like walking around the edges. Given: each side = 4 **Perimeter of a square = 4 × side length** So: Perimeter = 4 × 4 = **16** Think of it this way: You're adding all four sides together: 4 + 4 + 4 + 4 = 16 **Why the wrong options tempt you** - **A) 4** — This is just one side length. You forgot to go around the whole square! - **B) 8** — You only counted two sides (maybe opposite sides). A square has four sides, not two. - **C) 12** — You counted three sides. Close, but you missed one! **Quick takeaway** For **any square**, just multiply the side by 4: Perimeter = 4s. If one side is 4cm, walk around all four sides → 4 × 4 = 16cm. Simple!

AI Explanation

**The reasoning** "Half of 50" means you're **dividing 50 into two equal parts**. In mathematical terms: ½ × 50 = 50 ÷ 2 = **25** Think of it practically: If you have ₦50 and share it equally between two people, each person gets ₦25. That's what "half" means — one part out of two equal parts. **Why the wrong options tempt you** - **A) 20** — You might rush and think "half sounds like 20-something" without calculating. Or you confused it with "two-fifths" (2/5 × 50 = 20). - **C) 30** — This could trick you if you mistakenly did 50 − 20 instead of 50 ÷ 2. It's a common mental slip. - **D) 50** — Choosing this means you didn't divide at all — you just kept the original number. **Quick takeaway** "Half" always means **divide by 2** — whether it's half of money, marks, or any number; ½ × n = n ÷ 2.

AI Explanation

**The reasoning** To solve 3x = 9, we need to **isolate x** — get x alone on one side of the equation. The principle here is: **Whatever you do to one side, do to the other side.** Since x is being multiplied by 3, we do the opposite operation (division) to both sides: 3x = 9 Divide both sides by 3: 3x ÷ 3 = 9 ÷ 3 x = 3 Check it: 3(3) = 9 ✓ **Why the wrong options tempt you** **A) 1** — You might confuse this with solving 3 + x = 9 (which would give x = 6, not even option A!). Don't mix up addition and multiplication. **B) 2** — Maybe you thought "3 × 2 is close..." but maths demands exactness. 3 × 2 = 6, not 9. **D) 9** — This is just repeating the number you see in the equation. Remember: you're solving *for* x, not just picking a number from the question. **Quick takeaway** To solve ax = b, always divide both sides by the coefficient (the number stuck to x) — here, x = b/a = 9/3 = 3.

AI Explanation

**The reasoning** "Difference" in mathematics means **subtraction** — specifically, the result when you subtract the smaller number from the larger one. So: **12 − 5 = 7** Think of it this way: if you have ₦12 and spend ₦5, how much remains? Seven naira. That's your difference. **Why the wrong options tempt you** - **Option A (5)**: You might pick the smaller number by mistake, thinking "difference" means one of the original values. - **Option B (6)**: Common calculation error — maybe you miscounted: 12 − 5 = 6? Check your subtraction carefully. - **Option D (10)**: This trap catches students who **add** instead of subtract (5 + 5 = 10, or thinking of rounding). **Quick takeaway** *"Difference = Big minus Small"* — always subtract the smaller number from the bigger one, and double-check your arithmetic. Simple questions like this are meant to test your attention to detail, so slow down and compute carefully!

AI Explanation

8 × 7 = 56.

AI Explanation

25% × 200 = 50.

AI Explanation

Area = length × width = 8 × 5 = 40 cm².

AI Explanation

3/4 + 2/4 = 5/4 = 1 1/4.

AI Explanation

(4 + 8 + 12) ÷ 3 = 24 ÷ 3 = 8.

AI Explanation

Perimeter = 4 × side = 4 × 6 = 24 cm.

AI Explanation

0.5 = 5/10 = 1/2 (in lowest terms).