IMO Maths Tricks
LEARN • PRACTISE • ACHIEVE
Small tricks.
Big “I got it!”
moments.
Three useful IMO maths tricks to help young problem-solvers spot patterns, calculate faster and build confidence.
Olympiad maths rewards a curious mind. Sometimes, a small change in how you look at a question makes the calculation much easier. Here are three IMO maths tricks—one each for Classes 3, 4 and 5—with worked examples and a quick challenge.
Make a round number
Adding 9, 19 or 29? First add 10, 20 or 30, then subtract 1. Numbers close to multiples of 10 are your clue!
Find 47 + 29. Since 29 is one less than 30:
Add 30 to get 77. Take away the extra 1. Done!
Where it helps: Mental maths, addition puzzles and word problems involving totals.
✏️ Your turn: What is 68 + 19?
While solving IMO Previous Year Papers Class 3, look for numbers close to multiples of 10 and try this method.
Pair numbers to add faster
A long addition can become a short multiplication. Pair the smallest number with the largest, then work your way inwards.
Find the sum of the numbers from 1 to 20.
Continue the pattern: 10 pairs, each with a total of 21.
Where it helps: Number series, counting problems and sums of consecutive numbers.
✏️ Your turn: Add the numbers from 11 to 20.
Answer: 5 × 31 = 155
Practise spotting these patterns in IMO Previous Year Papers Class 4.
Count rectangles with line pairs
Counting shapes one by one can lead to missed rectangles. Instead, choose two vertical lines and two horizontal lines. These four lines form exactly one rectangle.
How many rectangles are in this complete grid?
4 vertical boundary lines
3 horizontal boundary lines
- Choose two vertical lines.
4 × 3 ÷ 2 = 6 pairs. - Choose two horizontal lines.
3 × 2 ÷ 2 = 3 pairs. - Multiply the choices.
Each vertical pair works with each horizontal pair.
Where it helps: Figure-counting and visual reasoning questions.
✏️ Your turn: Count the rectangles in a 2-column, 2-row grid.
Answer: 3 × 3 = 9 rectangles
Use IMO Previous Year Papers Class 5 to practise spotting small rectangles, larger rectangles and combinations of cells.
Understand it. Try it. Make it stick.
A shortcut becomes useful when students understand why it works and when to use it. Start without a timer, check mistakes, then try similar questions under timed conditions.
Explore IMO Previous Year Papers for Classes 1, 2, 3, 4, 5, 6, 7, 8, 9 and 10. Choose your child’s class and build a regular practice routine.
Ready for your next “I got it!” moment?
With SOF Olympiad Trainer, combine Previous Year Papers with chapter-wise practice and mock tests to build accuracy, confidence and smarter problem-solving habits.
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