The reasoning core of the Aon assessment differs from classic aptitude tests in one important way: rather than long word problems, the modules typically present small data sets — tables, statements, rule systems — and fire short questions at you against a hard per-question or per-module clock. Speed of orientation matters as much as raw ability.
The task families
Numerical reasoning: reading small tables or figures and answering quick calculation and estimation questions — arithmetic fluency under time pressure is the foundation.
Verbal reasoning: judging whether statements follow from short passages or data, with true / false / cannot-say style logic.
Deductive and inductive logic: spotting the rule in grids, sequences or symbol sets and applying it — the family where format familiarity pays off most, because the item styles are unusual on first sight.
How to prepare
Start with the format replicas, because they mirror the real modules item for item: Data Interpretation for the scales-style numerical reasoning from small tables and charts, Equation Completion for the fast numeracy items (now in the real select-and-place digit format), Verbal Reasoning for the true/false/cannot-say verbal module, Word Knowledge for the speeded closest-meaning vocabulary items, Odd One Out, Matrix Transformations and Grid Classification for the three inductive-reasoning formats, and Switch Challenge for the operator-deduction format. Underneath them, rotate the general trainers daily: Mental Math for numerical fluency, Sequences and Non-Verbal Reasoning for rule-finding, and Analogies and Syllogisms for the verbal-logical side. Because the real modules are short and brutally timed, practise in the same spirit — full-speed timed runs, then review your errors — and use your score trends to decide where the next session goes.