Mental Maths Tricks: Solve Questions in Seconds
With only 15-30 seconds per question on QuizOxa, mental arithmetic speed is critical. These tricks will help you calculate faster and think more clearly under pressure.
📋 What's Inside
Why Mental Maths Matters in Quizzes
Mathematical quiz questions don't require advanced calculus, but they do require fast, accurate mental calculations. Most maths questions in general knowledge quizzes test number sense, patterns, and key mathematical facts rather than complex problem solving.
The Science of Speed Arithmetic: Brain Plasticity & Math Training
Scientific studies in cognitive psychology reveal that speed math isn't an innate talent reserved for geniuses, but rather a trainable skill that leverages neuroplasticity. When you practice mental arithmetic, your brain actively adapts by strengthening the neural connections between the visual cortex (where you visualize numbers) and the parietal lobe (specifically the intraparietal sulcus, which handles numerical magnitude processing).
Furthermore, training your working memory through speed calculations improves what researchers call "cognitive load management." According to research on mental calculation training published in Frontiers in Human Neuroscience, automizing basic arithmetic operations (like multiplying by 11 or dividing by 5 using the shortcuts below) frees up precious prefrontal cortex capacity. This allows you to stay calm under intense quiz timers, quickly spot trick questions, and reason about complex logic problems without experiencing cognitive fatigue.
Essential Numbers Every Quiz Player Should Know
5 Powerful Mental Maths Shortcuts
💡 Multiplying by 11
For any two-digit number, add the two digits together and place the result in the middle. For example: 72 × 11 → 7_(7+2)_2 = 792. If the sum exceeds 9, carry over: 87 × 11 → 8_(8+7)_7 → 8+1_5_7 = 957.
💡 Squaring numbers ending in 5
Take the tens digit, multiply it by itself plus one, then append 25. For example: 35² → 3×4=12, then append 25 = 1,225. And 75² → 7×8=56, append 25 = 5,625.
💡 Percentage shortcut
To find X% of Y, switch them around, it's the same result. 8% of 50 = 50% of 8 = 4. This makes difficult-looking percentages trivially easy when one number is a simple fraction of 100.
💡 Multiplying by 9
Use the finger trick: hold out 10 fingers. To multiply 9 × 7, fold down your 7th finger. You have 6 fingers to the left and 3 to the right = 63. Works for 9×1 through 9×10.
💡 Quick division by 5
Dividing by 5 is the same as multiplying by 2 and then dividing by 10. For example: 340 ÷ 5 → 340 × 2 = 680 → 680 ÷ 10 = 68.
Common Maths Quiz Topics
- Prime numbers: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29... (2 is the only even prime)
- Fibonacci sequence: 0, 1, 1, 2, 3, 5, 8, 13, 21, 34... (each number = sum of previous two)
- Powers of 2: 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, 1024...
- Roman numerals: I=1, V=5, X=10, L=50, C=100, D=500, M=1000
- Geometric shapes: Know the formulas for area of circle (πr²), triangle (½bh), and rectangle (lw).
Frequently Asked Questions
❓ What is the fastest way to multiply a number by 11 in your head?
✅ Add the two digits of the number together and place the sum in the middle. For example, to multiply 72 by 11, add 7 and 2 to get 9, and place it in the middle to get 792.
❓ How can I calculate percentages quickly in a quiz?
✅ Use the percentage reversal trick: X% of Y is equal to Y% of X. For instance, calculating 8% of 50 is the same as calculating 50% of 8, which is a simple 4.
❓ What is the shortcut for dividing a number by 5?
✅ Multiply the number by 2 and then divide by 10 (move the decimal point one place to the left). For example, 340 divided by 5 is equal to (340 × 2) / 10 = 68.
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