Math explained

Short, clear explanations of the maths learned between the ages of about 7 and 15. Each page gives the rule or the method, a worked example or two, the mistakes people actually make, and the part usually left out: why it works at all.

• Divisibility rules

  Tell whether a number divides exactly by 2 to 13, without doing the division.

  12 lessons

• Factors and primes

  What a prime is, how to break a number into primes, and the HCF and LCM.

  6 lessons

• Written methods

  Long addition, subtraction, multiplication and division, decimals included.

  6 lessons

• Number facts

  Adding and taking away small numbers, the times tables and division facts.

  4 lessons

• Fractions

  What a fraction is, comparing and equal fractions, and adding, taking away, multiplying and dividing them.

  7 lessons

• Shapes and space

  Naming flat shapes and solids, counting sides, corners, faces and edges, and angles.

  7 lessons