Non-Calculator Techniques for IGCSE Maths
Papers 1 and 2 do not allow calculators. Strong mental arithmetic and efficient written methods are essential. This guide covers the key techniques you need to practise.
Mental Arithmetic
Fast, accurate mental maths saves time and reduces errors. Focus on times tables, powers of small numbers, and common fraction-decimal-percentage equivalents.
Tips
- Know all times tables to 12×12 instantly
- Memorise squares up to 15² and cubes up to 5³
- Learn common conversions: 1/8 = 0.125, 3/8 = 0.375, etc.
Written Methods
For calculations too large to do mentally, use efficient written methods. Long multiplication, short division, and column addition must be quick and reliable.
Tips
- Practise long multiplication with 3-digit numbers daily
- Use the bus stop method for short division
- Break complex calculations into simpler parts
Estimation and Checking
Estimation helps you spot wrong answers immediately. Round numbers to 1 significant figure and compute a rough answer to compare against your exact answer.
Tips
- Round each value to 1 significant figure for a quick estimate
- Check your answer is the right order of magnitude
- Use inverse operations to verify: if you multiplied, divide back
Key Takeaways
- Memorise times tables, squares, and key conversions
- Practise written methods until they are automatic
- Always estimate to catch errors
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Frequently Asked Questions
How long should I practise non-calculator skills?
Aim for 10–15 minutes of mental arithmetic practice daily in the weeks before your exam. Use flashcards or timed drills for times tables and fraction conversions.
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