Vedic Mathematics & other speed math tricks

Also do check my blog on Trachtenberg speed calculation method

Squaring a number

Finding a square of a number is easy this way:

Let’s find the square of 94

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We will take the base as 100, 100 - 94 = 6 & 6^2 = 36, 94 - 6 = 88 so the answer is 8836

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Now let’s find the square of 97

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We will take the base as 100, 100 - 97 = 3 & 3^2 = 09, 97 - 3 = 94 so the answer is 9409

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Now let’s find the square of 84

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We will take the base as 100, 100 - 84 = 16 & 16^2 = 256, 84 - 16 = 68 so the answer is 6(8+2)56 = 6(10)56 = 7056

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in the above answer the bold part is called RHS and it must contain as many digits as the number of 0s of the base, here base was 100 so 2 digits. The underlined portion is called LHS and it can contain as many digits as needed.

Now for numbers like 112, i.e. numbers which are above their base, in that case do the following 100 + 12 = 112, 112 + 12 =124, 12 X 12 = 144. The number becomes, 124 + 144 = 12544. The other rules remain the same.

Multiplying numbers like 38 X 32, 75 X 75 etc

Next we will learn how to multiply 2 numbers whose sum of tens digit is 10, and the rest of the digits are equal. This trick is particularly useful for finding the squares of numbers like 25, 95, 75 and so on..

38 X 32 = first few digits 3(3 + 1)  last 2 digits 8 X 2 → 1216

75 X 75 = 7 X 8 → 56, 5 X 5 → 25 ⇒ 5625

Source:

BullsEye App

Quantum CAT