AMO Grade 4 · 2. Clever calculation
Look before you calculate: right order, friendly pairs, common factors, pairs in equally spaced lists, and quick work with fractions.
Work out expressions in the correct order and regroup + and − terms.
Use 2 × 5, 4 × 25 and common factors to multiply quickly.
Count the terms of an equally spaced list and find its sum or alternating sum.
Find a fraction of a number, add, compare and simplify fractions.