Logical reasoning

Number Series

Each sequence follows a hidden rule. Find the pattern and continue it. Number series test inductive reasoning, a core part of most pilot aptitude batteries.

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About this test

What this test measures

This measures inductive reasoning: spotting the rule behind a sequence of numbers and extending it. It is a classic test of fluid intelligence, the raw problem-solving airlines value because learning new systems and procedures leans on it.

How to improve your score

Look first at the differences between terms, then at the differences of those differences.
Test for multiply, divide and alternating patterns when simple addition does not fit.
If one rule does not work, switch hypothesis quickly rather than forcing it.

Good to know

Write the gaps

Note the difference between each pair of terms. A constant gap is addition; a growing or repeating gap is a step or alternating rule; if the terms multiply, look at the ratios instead.

Check two ways before you commit

Confirm your rule predicts a known term as well as the missing one. A rule that fits only part of the series is the wrong rule, and the options usually include the trap it leads to.

Frequently asked questions

What kinds of rules appear?

Constant steps, growing steps, multiplication, and alternating patterns. Look at the differences between terms first; that usually reveals the rule.

What is a good strategy?

Write the gaps between consecutive numbers. If the gaps are constant it is addition; if they grow or repeat there is a step or alternating rule; if terms multiply, try ratios.

Is this inductive or deductive reasoning?

Inductive: you infer a general rule from specific examples, then apply it. It is one of the strongest predictors of general problem-solving ability.

Related exercises

Deductive Logic

Two statements, one conclusion that must follow.

Abstract Reasoning

Pick the figure that completes the pattern.

Figural Series

Spot the pattern and pick the next shape.

Figural Odd One Out

Find the shape that breaks the pattern.

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