Mental arithmetic, the process of performing calculations in your head without the aid of physical devices, is a skill that can be honed with practice and the right techniques. Here's how you can improve your mental math abilities:
Strategies for Effective Mental Arithmetic
Effective mental arithmetic involves several strategies to simplify calculations and perform them quickly and accurately. Here are some key techniques to master:
1. Breaking Down Problems
Complex problems can seem daunting, but breaking them down into smaller, more manageable parts makes them easier to handle:
- Example: Instead of calculating 17 x 6 directly, think of it as (10 x 6) + (7 x 6). That's 60 + 42, making the answer 102.
2. Working From Left to Right
Often, we learn to calculate from right to left. However, for mental arithmetic, working from left to right can be more intuitive:
- Example: To add 35 + 27 mentally, start with the tens: 30 + 20 = 50, then add the ones: 5 + 7 = 12. Finally, combine these results: 50 + 12 = 62.
3. Rounding and Adjusting
Rounding numbers to the nearest ten or hundred can simplify calculations:
- Rounding Up: If you need to add 48 + 33, you could round 48 to 50, add 50 + 33= 83, and then subtract 2 (because we added 2 in the rounding stage) 83 - 2 = 81.
- Example: For 198 + 45, think of 200 + 45 = 245, then subtract 2 to correct for the rounding, resulting in 243.
4. Leveraging Multiplication Hacks
Certain multiplication tricks can make calculations quicker:
- Multiplying by 10s, 100s, 1000s : Add the appropriate amount of zeros to the number. E.g., 5x10=50; 5x100=500; 5x1000=5000.
- Multiplying by 5: Divide the number by two then multiply by 10. E.g., To multiple 26 by 5. Divide 26 by 2 = 13 then multiply by 10 to get 130
- Multiplying by 11 To multiply by 11 you need to add the digits and put it in between. E.g., for 12 x 11; 1+2=3 then put that between the 1 and 2, which is 132. Another example is 26 x 11. 2+6=8. Put 8 between 2 and 6 to make 286.
5. Calculating Percentages
Percentages can be calculated mentally by moving the decimal:
- Example: To find 10% of 250, move the decimal one place to the left, resulting in 25. To find 1% of 250, move the decimal two places to the left, resulting in 2.5. You can use this to work out other percentage rates by dividing or multiplying. For example, 5% of 250 would be 2.5 x 5 = 12.5.
- To find 20% of a number you could take 10% and multiple by 2
6. Making Guesstimates
Sometimes an accurate answer isn’t necessary. Guesstimating can give you a quick approximate answer to a problem.
- Example: You have to go to the shops and you have £20. You see three items that cost £7.95, £4.20 and £3.30. By rounding those items you could guesstimate that you have roughly £15 worth of items, which leaves you with roughly £5 left.
Practical Tips for Improving
- Practice Regularly: Consistent practice is key. Start with simple calculations and gradually increase the complexity.
- Use Flashcards: Create flashcards for multiplication, division, and addition to improve speed and accuracy.
- Start with Simple Operations: Begin with addition and subtraction before moving to multiplication and division.
- Challenge Yourself: Look for opportunities to calculate without a calculator.
- Focus: Minimize distractions when practicing mental math.
By practicing these techniques and staying consistent, you can significantly improve your mental arithmetic skills.
