Salam Academy
Papers 1–3 · Module

Number

5 subtopics≈ 150 min in total
  1. Types of number, factors and multiples

    Every whole number is built from primes, like a molecule from atoms. Writing numbers as products of primes makes highest common factors and lowest common multiples quick. Along the way you meet the families of numbers: integers, squares, cubes, rational and irrational numbers.

    ≈ 30 min
  2. Fractions and decimals

    To add or subtract fractions, give them a common denominator. To multiply, multiply tops and bottoms; to divide, flip the second fraction and multiply. Every fraction is a terminating or recurring decimal, and every recurring decimal can be turned back into a fraction.

    ≈ 30 min
  3. Indices and standard form

    Multiply powers of the same base by adding indices, divide by subtracting, and raise a power to a power by multiplying. a0=1a^0=1, a−n=1ana^{-n}=\dfrac1{a^n}, and a1na^{\frac1n} is the nnth root. Standard form A×10nA\times10^n (1≤A<101\le A<10) writes huge and tiny numbers compactly.

    ≈ 30 min
  4. Surds

    A surd is a root that can't be simplified to a whole number, like 2\sqrt2. Keep surds exact: pull out square factors (48=43\sqrt{48}=4\sqrt3), collect like surds, and remove surds from denominators by multiplying top and bottom by the right surd or by the conjugate.

    ≈ 30 min
  5. Estimation and limits of accuracy

    Round to significant figures or decimal places, and estimate answers by rounding every number to 11 s.f. A measurement rounded to the nearest unit could really be up to half a unit either side: those are its bounds. For calculations, choose the bounds that make the answer biggest or smallest.

    ≈ 30 min