Quantitative Reasoning
What the Quantitative Reasoning battery measures
The Quantitative Reasoning battery tests pattern-finding with numbers, not calculation speed. Upper-level subtests are Number Analogies, Number Puzzles, and Number Series; primary levels use pictured objects and simpler quantities. You must infer the rule that generates a set of numbers and apply it consistently.
Core rules
- Number analogy (A : B :: C : ?). Find the operation that changes A into B, then apply the same operation to C. Test whether the rule is additive, multiplicative, or a combination (e.g., ×3 + 1). Check order: “divide by 2” is not the same as “subtract 2.”
- Number puzzle. Treat the item as a balance. Undo operations in reverse order, or substitute the answer choices. Whatever you do to one side must be done to the other.
- Number series. Compute first differences. If they are not constant, compute second differences or look for a ratio. Also check for two interleaved sequences (every other term) and for square or cube patterns.
Worked example
Series: 2, 6, 12, 20, ?
Options: 28, 30, 32, 36.
First differences: 6 − 2 = 4; 12 − 6 = 6; 20 − 12 = 8. The differences increase by 2, so the next difference is 10 and the missing term is 20 + 10 = 30. A second check: the terms are 1×2, 2×3, 3×4, 4×5, so the next is 5×6 = 30. Option 28 comes from adding 8 again; 32 comes from adding 12; both ignore the changing difference.
Traps that cost marks
- Assuming a constant difference after seeing only the first two terms.
- Applying a rule in the wrong direction, especially with division or subtraction.
- In number puzzles, performing an operation on only one side of the equation.
- Choosing an answer that fits one pair but breaks the rest of the series.
- Rushing arithmetic and misreading the operation sign; the distractors are often built from exactly those slips.