Number questions look easy and punish haste: fraction–decimal–percentage conversion, standard form, ratio splitting, compound percentage change, bounds from rounded data, and estimation where one significant figure plus cancelling zeros beats long multiplication. Mental arithmetic is the whole game — calculators are banned.
Traps are engineered: 'increase by 200%' versus 'increase to 200%', bounds asked the wrong way round, and estimation options spaced to catch calculator-habit precision. Round deliberately, track upper/lower bounds explicitly, and sanity-check magnitude before moving on.
Study method: attempt five timed questions, log every miss with its topic code, redo misses from scratch within 48 hours, then re-attempt the topic a week later. Pair each hub with its drill link below and a fortnightly full mock.
Place this topic in the wider test with the syllabus checklist and Paper 1 vs Paper 2, learn the timing system in how to prepare, and check what scores mean in scores explained.