Quantitative Reasoning: Number Patterns and Symbol Logic
What this domain tests
Quantitative Reasoning measures numerical thinking rather than calculation speed. Level E items usually include number series (what comes next), numeric inference (symbols or function machines that stand for operations, or equations where a symbol replaces a number), number matrices (a grid with one missing value), and arithmetic reasoning (short word problems).
Concepts to master
- Common series rules. Add or subtract a constant, multiply or divide by a constant, add a growing amount (+1, +2, +3…), square or double-and-add, or alternate two rules.
- Differences first. Compute the gaps between consecutive terms before guessing. If the gaps themselves form a pattern, you have found the rule.
- Ratio check. If the gaps are irregular, divide each term by the previous one to test for multiplication.
- Symbol substitution. When a shape stands for an operation, translate the whole expression into ordinary arithmetic before solving, and follow order of operations.
- Matrix relationships. In a number grid, look for a rule across each row (often the same rule in every row) and check it down the columns as well.
Traps
Distractors come from stopping at the first plausible rule, from using differences when the rule is multiplication (or the reverse), and from ignoring an alternating pattern. In word problems, the trap is answering the wrong quantity - the number of items instead of the total cost, for example. Arithmetic slips on multi-step items also cost points.
Rule of thumb
Before choosing, verify your rule on at least two earlier terms, not just the last one. A rule that predicts the whole series is reliable; one that explains only the final jump is not.
Worked example
Find the next term: 2, 3, 5, 9, 17, ?. Differences are 1, 2, 4, 8 - each double the previous. The next difference is 16, so the answer is 17 + 16 = 33. Notice that checking two steps (1 → 2 → 4) confirms the doubling; a single difference would not have been enough.