Mental Maths: Mental maths is the process of doing mathematical operations alone using the human brain, devoid of the need for calculators or other aids. When calculators are unavailable or the computation time is significantly less than the computation time, people resort to mental maths.
Mental maths can be used to do arithmetic operations quickly for calculations. Primary school students in grades 1 through 5 can practise mental maths by employing shortcuts and time-saving techniques. Specific strategies created for different types of math problems are included in mental math techniques. Since their capacity for mental computation is the greatest, very few people are called mental calculators. The majority of the methods depend on the decimal system of numbers. Which methods to utilise is determined by the choice of radix.Related Links -
i) Direct computation
Consider two numbers a and b. The calculation is performed digit by digit when the second number's digits are smaller than the first number's digits. For example, find the difference of 872 – 41. Subtract 1 from 2 in the one’s place and 4 from 7 in the 10’s place. The final answer is 831.ii) Indirect computation
Indirect computation refers to solving problems by using alternate methods or intermediary steps rather than direct calculation. It often involves breaking a complex problem into simpler parts or using properties of numbers to find the solution. For example, instead of multiplying two large numbers directly, you can decompose one number into smaller components or use approximation methods to get a quicker answer.iii) Borrow method
The borrow method, commonly used in subtraction, helps when the top digit in a column is smaller than the bottom digit. To perform this, you "borrow" 1 from the next higher place value (e.g., the tens column), adding 10 to the smaller digit to allow subtraction. This is typically used in multi-digit subtraction to avoid negative results in individual columns. Subtract the numbers from left to right. For example:1 2 | 1 | 11 2 | 121 | 21 2 | 441 |
2 2 | 4 | 12 2 | 144 | 22 2 | 484 |
3 2 | 9 | 13 2 | 169 | 23 2 | 529 |
4 2 | 16 | 14 2 | 196 | 24 2 | 576 |
5 2 | 25 | 15 2 | 225 | 25 2 | 625 |
6 2 | 36 | 16 2 | 256 | 26 2 | 676 |
7 2 | 49 | 17 2 | 289 | 27 2 | 729 |
8 2 | 64 | 18 2 | 324 | 28 2 | 784 |
9 2 | 81 | 19 2 | 361 | 29 2 | 841 |
10 2 | 100 | 20 2 | 400 | 30 2 | 900 |
v) Finding roots
Finding roots, particularly square roots or cube roots, involves determining which number, when multiplied by itself (or cubed), gives the original number.vi) Approximation of common logarithms