CAST numerical reasoning

CAST numerical reasoning shows you a small grid of figures — a table, or the same figures drawn as a bar or line chart — and asks one calculation over it. Five numeric options follow, one of which is correct.

The arithmetic never goes beyond percentages, ratios, averages and compound growth. What makes the test hard is time: two minutes per question including reading the table, deciding what is being asked, and computing it. There is no partial credit for having set the calculation up correctly.

The calculation types that come up

• Totals and subtotals — a row total across periods, a column total across categories, or the combined total of a named subset.
• Differences and ratios — how much a figure moved, or how one category compares to another in the same period.
• Percentage of a total — what share one category represents, and how that share moved between two periods.
• Percentage change — including change in a total rather than in a single cell, and change expressed in percentage points over a table of rates.
• Projection — apply a stated growth rate for one period or compound it over several, or work backwards from a stated share to an implied total.

Charts are the same question in a different coat

The same figures can arrive as a table one sitting and as grouped bars the next. Nothing about the question changes — the same rows, the same computation, the same key. A candidate who can only read one layout has a gap the real exam will find, so practice here deliberately serves both.

Chart values are always drawn so that every bar top and every marker lands exactly on a gridline. If you find yourself estimating a value, you are reading the axis wrong rather than being asked to approximate.

Working faster without working sloppier

1. Read the question first, then go to the table for the two or three cells it actually needs. Reading the whole grid is time spent on figures you will not use.
2. Check the unit in the heading before you compute, not after. It is the cheapest error to prevent and the most expensive to make.
3. Estimate first where you can. Knowing the answer is "a bit over 20%" kills three options before you do any exact arithmetic.
4. Move on. Ten questions in twenty minutes means one hard item cannot be allowed to eat two others. Practice untimed until the formats are automatic, then sit the full timed mock.

An on-screen calculator, as in the real test

Practice includes a calculator you can open on any numerical question, and it keeps what you were mid-way through if you close it to look back at the table.