How to Calculate Percentages Mentally

In this post we will explain how to calculate percentages mentally and quickly using a Vedic Math technique. We will use a popular multiplication technique in Vedic maths that can be used to calculate also approximate percentages mentally.

We will understand this technique by applying it on calculation of percentages of two digit numbers and three digit numbers.

Using Vedic Math Technique:

In Vedic Maths, a general strategy that we use to multiply any two numbers is known as Urdhva Tiryak or the Vertical and Cross Wise technique. This technique can be applied from left to right or from right to left. We recommend the left to right approach as,

1. A mental calculation approach typically involves left to right calculation.
2. In addition to that it will be helpful in approximation.

Now, let’s understand this technique by applying it to calculating percentages. Let’s say we would like to calculate the value of 46% of 51. 46% of 51 is equivalent to multiplying 46 and 51 and dividing the resulting value by 100. Thus, as shown in the image below we first multiply 46 and 51 using the vertical and cross-wise technique.Now according to the technique, in the product of 51 and 46

1. We first multiply 5 and 4. The resulting value 20 becomes the left most part of the answer.
2. Then we will take the sum of cross products 5 and 6, 4 and 1 => 5×6 + 4×1 = 34. The excess 3 in 34 will be carried over to the left part 20 which becomes 23.
3. Next we take the product of the unit digits 1 and 6.

Thus we have the product of 46 and 51. Dividing the resulting value 2346 by 100 gives us the value of 46% of 51 => 23.46.

The advantage with the above approach as pointed out earlier is, in most cases we do not even have to calculate the step 3 above. At the end of step 2 we have an approx value which is 23.4.

Video:

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