Mathematics can sometimes seem challenging, but with the right techniques, solving math problems can become quicker and easier. In this blog, we’ll explore ten math tricks that can save you time, improve your calculation skills, and boost your confidence.
These tricks are especially helpful for students preparing for exams, professionals working with numbers, or anyone looking to sharpen their math skills. So let’s dive in and make math easy!
1. Multiplying by 9 with Your Fingers
One of the quickest ways to multiply single-digit numbers by 9 is using your fingers. It’s easy, visual, and fun.
- How It Works:
- Hold your hands out in front of you with fingers spread.
- For any number (1-9), bend down that finger number.
- Count fingers to the left of the bent finger (this is the tens place), and to the right (this is the units place).
- Example: For 9 x 3:
- Bend down the 3rd finger.
- 2 fingers are left of the bent finger, 7 fingers are on the right.
- Answer = 27.
2. Squaring Numbers Ending in 5
If you’re squaring a two-digit number ending in 5, this trick simplifies the process.
- How It Works:
- Take the first digit, multiply it by itself plus one.
- Append 25 to the result.
- Example: For 35²:
- First digit is 3. 3 x (3+1) = 12.
- Append 25: Answer = 1225.
3. Quick Multiplication by 11
For two-digit numbers, multiplying by 11 can be done in seconds with this trick.
- How It Works:
- Separate the two digits, then add them.
- Insert the sum between the original digits.
- Example: For 32 x 11:
- Separate into 3 and 2. Add 3 + 2 = 5.
- Place the sum between 3 and 2: Answer = 352.
4. Divisibility Shortcuts
Knowing if a number is divisible by another can help simplify problems or check answers.
- Divisibility by 3: Sum the digits; if the sum is divisible by 3, so is the number.
- Divisibility by 4: If the last two digits form a number divisible by 4, the number is divisible by 4.
- Divisibility by 9: Sum the digits; if divisible by 9, so is the number.
5. Subtracting from 1000, 100, or 10
For numbers close to these round numbers, subtracting is straightforward with this method.
- How It Works:
- Subtract each digit individually from 9, except the last digit, which you subtract from 10.
- Example: For 1000 – 274:
- Subtract 2 from 9 = 7, 7 from 9 = 2, and 4 from 10 = 6.
- Answer = 726.
6. Doubling and Halving for Easier Multiplication
This trick is useful for multiplying one even and one odd number.
- How It Works:
- Divide the even number by 2 and double the odd number. Repeat until it’s easy to calculate.
- Example: For 48 x 25:
- Halve 48 (24) and double 25 (50), so 24 x 50 = 1200.
7. Multiplying by 5 Quickly
If you need to multiply a number by 5, this shortcut simplifies it.
- How It Works:
- Divide the number by 2, then multiply by 10.
- Example: For 76 x 5:
- 76 ÷ 2 = 38, then 38 x 10 = 380.
8. Converting Percentages to Decimals for Fast Calculation
Using decimals can make percentage calculations quicker.
- How It Works:
- Move the decimal two places left to convert percentage to a decimal.
- Multiply this by the base number.
- Example: For 20% of 50:
- 20% = 0.2, so 0.2 x 50 = 10.
9. Multiplying Large Numbers with Round Numbers
Multiplying large numbers ending in zeros can be simplified by removing the zeros, multiplying the core numbers, and then adding the zeros back.
- How It Works:
- Remove zeros temporarily, multiply, then add the zeros back.
- Example: For 300 x 400:
- Ignore zeros temporarily: 3 x 4 = 12.
- Add the four zeros: Answer = 120,000.
10. The Power of Size Charts for Mental Math Practice
Using a size chart can help visualize and practice mental math techniques, improving speed and accuracy over time. Here’s a handy chart that outlines time-saving methods for specific operations:
| Operation Type | Shortcut | Example |
|---|---|---|
| Multiplication by 9 | Finger trick | 9 x 3 → 27 |
| Squaring numbers (5) | First digit x (n+1), add 25 | 35² → 1225 |
| Multiplication by 11 | Insert digit sum | 32 x 11 → 352 |
| Doubling & Halving | Split even and odd numbers | 48 x 25 → 1200 |
| Multiplying by 5 | Halve and x10 | 76 x 5 → 380 |
Final Thoughts
These tricks are valuable tools for mental math that make solving problems quicker and more intuitive. Integrating these techniques into your routine will gradually increase your math speed and accuracy, helping you excel in exams, work, and daily life. Start practicing these tricks and see how they transform your approach to math!