NSW Selective — Mathematical Reasoning

Mathematical Reasoning: Selective Test Practice & Examples

Mathematical Reasoning on the NSW Selective test is 35 questions in 40 minutes, multiple choice with five options each, and no calculator is allowed. It rewards problem solving, not rote calculation: most questions dress a curriculum idea up in a real situation and ask your child to work out what to do, then do it accurately under time pressure. This page sets out the topics it covers, five worked examples at genuine test difficulty, the calculator and equipment rules, and how to pace 35 questions across 40 minutes so your child never runs out of time.

Topics it covers

Mathematical Reasoning draws entirely on the NSW curriculum up to Year 6, but questions apply those ideas in unfamiliar, multi-step situations. The strands your child should be comfortable with are:

  • Number and operations — place value, factors and multiples, order of operations, and mental strategies for large numbers.
  • Fractions, decimals and percentages — converting between them, finding fractions of quantities, and simple percentage increase or decrease.
  • Ratio and proportion — sharing in a given ratio and scaling recipes, maps or mixtures up and down.
  • Measurement — length, area, perimeter, volume, mass, time, and unit conversions.
  • Geometry — properties of 2D shapes and 3D solids, angles, symmetry, and simple coordinate work.
  • Data — reading and interpreting tables, graphs and simple averages.
  • Multi-step word problems — combining two or three of the above in a single question, which is where most of the difficulty lives.

Five worked examples

These are original FunThinkers questions written at Selective difficulty — one each for ratio, percentages, measurement and geometry, rate and speed, and number patterns. Each has five options. Work them out on paper first, then reveal the answer.

Example 1

Fraction & ratio: A biscuit recipe uses flour and sugar in the ratio 5 : 2. If the recipe uses 350 g of flour, how much sugar does it need?

  • A. 70 g
  • B. 105 g
  • C. 140 g
  • D. 175 g
  • E. 245 g
Show answer

Answer: C — 140 g.
5 parts of flour = 350 g, so 1 part = 70 g. Sugar is 2 parts = 2 × 70 = 140 g.

Example 2

Percentage: A jacket costs $80. In a sale it is reduced by 15%, and members get a further 10% off the reduced price. What does a member pay?

  • A. $60.00
  • B. $61.20
  • C. $62.00
  • D. $68.00
  • E. $72.00
Show answer

Answer: B — $61.20.
First reduction: $80 × 0.85 = $68. Further 10% off: $68 × 0.90 = $61.20. The two discounts must be applied one after the other, not added to 25%.

Example 3

Measurement & geometry: A rectangular garden bed is 12 m long and 8 m wide. A path exactly 1 m wide is laid all the way around the outside of the bed. What is the area of the path?

  • A. 20 m²
  • B. 40 m²
  • C. 44 m²
  • D. 48 m²
  • E. 140 m²
Show answer

Answer: C — 44 m².
The path adds 1 m to every side, so the outer rectangle is 14 m × 10 m = 140 m². The garden bed is 12 × 8 = 96 m². Path area = 140 − 96 = 44 m².

Example 4

Rate & speed: A train travels 210 km in 2 hours and 30 minutes. What is its average speed?

  • A. 70 km/h
  • B. 80 km/h
  • C. 84 km/h
  • D. 90 km/h
  • E. 105 km/h
Show answer

Answer: C — 84 km/h.
2 hours 30 minutes = 2.5 hours. Average speed = distance ÷ time = 210 ÷ 2.5 = 84 km/h.

Example 5

Number pattern: In a sequence, each term is found by doubling the previous term and then subtracting 3. The sequence begins 5, 7, 11, 19, … What is the next term?

  • A. 27
  • B. 31
  • C. 33
  • D. 35
  • E. 38
Show answer

Answer: D — 35.
The rule is “double, then subtract 3”: 2 × 19 − 3 = 38 − 3 = 35. (Check: 2 × 5 − 3 = 7, 2 × 7 − 3 = 11, 2 × 11 − 3 = 19.)

Calculator rules & mental strategies

There is no calculator and no dictionary in the Mathematical Reasoning section. Your child writes their working on paper with a pencil, so neat, organised working is worth practising in its own right — a tidy layout makes it far easier to spot a slip before choosing an answer.

Two habits pay off under these conditions. The first is estimation: before working a problem out exactly, form a rough sense of the answer, so an obviously wrong option can be ruled out and a careless mistake gets caught. The second is elimination: because every question has five options, testing or excluding options is sometimes faster than solving from scratch — for example, checking which option divides evenly, or which is the only one in a sensible range.

Pacing

The maths is 35 questions in 40 minutes, which is roughly 68 seconds per question on average. That average is the trap: a few hard questions will take much longer, so your child cannot afford to burn two or three minutes on any single one early on.

The reliable strategy is skip and return. Answer the questions that come quickly, flag anything that stalls, and move on — then come back with whatever time is left. Because it is multiple choice with no penalty for guessing, every question should have an answer marked before time runs out, even if a few are educated guesses. The goal in practice is to build the instinct for when to commit and when to move on, so real test time is spent on the questions your child can actually win.

Practise maths reasoning free

Sit Selective-style Mathematical Reasoning questions in the real format and get an instant, marked report.

Practise maths reasoning free

Frequently asked questions

Can my child use a calculator?

No. The Mathematical Reasoning section is done without a calculator, and no dictionary is allowed either. Working out is done on paper with a pencil, so mental maths and quick estimation matter.

How many maths questions are there?

The section has 35 questions to answer in 40 minutes — about 68 seconds each on average. Every question is multiple choice with five options.

What topics come up?

Number and operations, fractions, decimals and percentages, ratio, measurement, geometry, reading data from tables and graphs, and multi-step word problems — all drawn from the NSW curriculum. Nothing beyond what is taught by Year 6, but applied in less familiar ways.

How is this different from school maths?

School maths often tells you which method to use. Mathematical Reasoning hides the method inside a worded problem, so the challenge is deciding what to calculate. Questions are also faster-paced and multiple choice, which makes estimation and answer elimination genuinely useful.

Source: NSW Department of Education — Selective High School Placement Test. Last verified: July 2026.