Numbers & Estimation
Directed numbers, approximate values, primes and scientific notation.
Directed numbers: add, subtract, multiply and divideUse number-line sense and sign rules so directed-number calculations stay accurate under exam pressure.Numbers & Estimation· Mr ChanMCQ2
Approximate values and sensible estimationRound to a required accuracy, estimate products and quotients, and check whether an answer is reasonable.Numbers & Estimation· Mr ChanMCQ3
Rational numbers: fractions, decimals and recurring decimalsConvert between fractions and decimals, recognise recurring decimals, and keep rational arithmetic organised.Numbers & Estimation· Ms LamMCQ4
Prime factorisation, HCF and LCMWrite numbers as products of primes, then read off HCF and LCM — a frequent TSA-style opener.Numbers & Estimation· Mr ChanMCQ5
Scientific notation and large/small numbersConvert between ordinary form and a × 10ⁿ with 1 ≤ |a| < 10 — standard S3 index work.Numbers & Estimation· Mr ChanMCQ6
Directed numbers with brackets (challenge)Mixed operations with multiple brackets — the step that trips many S2–S3 students in timed papers.Numbers & Estimation· Ms LamMCQ7
Ordering directed numbers on the number lineCompare and arrange positive and negative integers for S2 foundation checks.Numbers & Estimation· Mr ChanMCQ8
Absolute value of directed numbersRead |a| as distance from zero and simplify expressions with absolute values.Numbers & Estimation· Ms LamMCQ9
Four operations mixed with directed numbersApply BODMAS carefully when signs and brackets appear together.Numbers & Estimation· Mr NgMCQ10
Rounding to decimal placesRound to 1, 2 or 3 decimal places using the next-digit rule.Numbers & Estimation· Ms ChuMCQ11
Significant figures in calculationsCount significant figures and round answers as papers require.Numbers & Estimation· Mr YipMCQ12
Converting fractions and decimalsMove fluently between fractions, terminating decimals and recurring decimals.Numbers & Estimation· Mr ChanMCQ13
Comparing rational numbersCompare fractions and decimals using common denominators or decimal form.Numbers & Estimation· Ms LamMCQ14
HCF and LCM word problemsChoose HCF for greatest shared size and LCM for repeating cycles.Numbers & Estimation· Mr NgMCQ15
Estimating square roots without a calculatorSandwich a root between consecutive squares to estimate its size.Numbers & Estimation· Ms ChuMCQ16
Operations in scientific notationMultiply and divide numbers written as a×10ⁿ and renormalise.Numbers & Estimation· Mr YipMCQ