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Mathematical Reasoning · one of four sections

Mathematical Reasoning for the maths olympiad

The largest section, and the one closest to school maths, but pitched a step sideways. The arithmetic is familiar; what is asked of it is not.

We have written 500 Mathematical Reasoning questions by hand across classes 3 to 8.

Try two of them

One from a class 4 paper and one from class 7, so you can see how the same section grows. Have a go before opening the answer.

3 pointsClass 4Question 11

What is the value of the digit 7 in the number 4,732?

Show the answer and how to see it

Answer: 700

Read the places from the right: 2 ones, 3 tens, 7 hundreds and 4 thousands. So the 7 stands for 7 hundreds, which is 700.

Why a child picks 7: 7 on its own is what the digit looks like, but its VALUE depends on its place, and it sits in the hundreds.

Sit the whole paper this came from
3 pointsClass 7Question 16

Three quarters of a number is 15 more than one third of the same number. What is the number?

Show the answer and how to see it

Answer: 36

Do not hunt for the number by trial. Take one third away from three quarters FIRST: that leaves five twelfths of the number, and five twelfths of it is 15.

Why a child picks 20: This divides 15 by three quarters. The 15 is the gap BETWEEN the two fractions, not three quarters of the number.

Sit the whole paper this came from

What this section actually tests

  • 1Number properties: factors, multiples, remainders, place value and what happens to them under an operation.
  • 2Fractions, decimals and percentages, usually needing two of the three in one question.
  • 3Geometry of shapes a child can draw: perimeter, area, angles, symmetry, nets and solids.
  • 4Measurement and unit change, where the trap is a unit rather than the arithmetic.
  • 5Algebraic thinking without algebra: a missing number that has to be reasoned back to.

The method, in order

Worth saying out loud the first few times. The order matters more than the speed.

  1. 1. Name what is being asked before you calculate

    Perimeter or area, factors or multiples, before or after. Half the lost marks in this section are a correct calculation of the wrong thing.

  2. 2. Work in one unit

    Convert everything to the smallest unit in the question before you start, and convert back at the end. Do not carry two units through the working.

  3. 3. Estimate first, then compute

    A rough answer takes five seconds and catches a decimal point in the wrong place, which is the single most common arithmetic slip.

  4. 4. Put the answer back into the question

    If the question says the total is 48, check your answer produces 48. This catches almost every reversed subtraction.

The four ways children lose marks here

These are not guesses. Each one is a wrong option we deliberately built into real questions, which is why every one of them feels reasonable at the time.

Answering the intermediate step

The fix: Underline the actual question. Many questions ask for the difference or the remainder after the thing you just worked out.

Mixing centimetres and metres inside one sum

The fix: Convert before you calculate, never during. Write the unit next to every number.

Treating "factor" and "multiple" as the same word

The fix: Factors go into it, multiples come out of it. Say which one out loud before starting.

Assuming a diagram is drawn to scale

The fix: Use the numbers written on it, never the look of it. Olympiad figures are often deliberately not to scale.

How many Mathematical Reasoning questions are on the paper

ClassMathematical ReasoningQuestions on the paper
Class 31035
Class 41035
Class 52050
Class 62050
Class 72050
Class 82050

Section names and the shape of the paper follow the Science Olympiad Foundation olympiad blueprint. We are not affiliated with them, these questions are our own, and the official pattern is theirs to confirm.

Questions parents ask

How much of the paper is Mathematical Reasoning?

In our papers it is 10 of 35 questions for classes 3 and 4, and 20 of 50 for classes 5 to 8, which makes it the biggest single section in the upper classes.

Does it go beyond the school syllabus?

Rarely in content, often in demand. The topics are ones a child has met, but a question may combine two of them, or ask for the condition under which something is true rather than for a value.

What is the fastest way to raise a score in this section?

Accuracy, not new topics. Most children lose more marks to unit slips, reversed subtractions and answering the intermediate step than to anything they had not been taught.

Should a child memorise formulas?

A small number, yes, mainly area and perimeter. Beyond that, memorising does less good than being able to check a formula by trying it on a simple case.

Practise it inside a whole paper

One section at a time is how you fix a weakness. A full timed paper is how you find out whether it is fixed.