Numbers you must never mix up
Mathematics · BECE · JSS (BECE)
Most JSS marks are lost on place value, fractions and directed numbers — not on “hard” topics.
What you need to know
- Place value: in 47,305 the 7 is 7 thousands, the 3 is 3 hundreds. Always name the place, not just the digit.
- LCM is the smallest number both divide into. HCF is the biggest number that divides both.
- A fraction is in lowest terms when the HCF of numerator and denominator is 1.
- To add fractions, same denominator first. To divide, multiply by the reciprocal.
- Negative numbers: two minuses make a plus when multiplying. On a number line, left is smaller.
- Standard form in JSS: a × 10ⁿ with 1 ≤ a < 10. 45,000 = 4.5 × 10⁴. 0.0032 = 3.2 × 10⁻³.
- Ratio 2:3:5 of ₦2,000 — add 2+3+5=10 parts, one part is ₦200, so ₦400 : ₦600 : ₦1,000.
- Percentage of a quantity: (percent / 100) × the quantity. Increase: multiply by (1 + r/100).
The mistake to avoid
Percentage profit is on COST price, not selling price, unless the question says otherwise.