Shortcut to multiply any number from 80-89 by 5

In the previous post we learnt how to multiply any number from 70 to 79 by 5 in seconds.Today we are going to learn another cool trick to multiply any number from 80 to 89 by 5 in seconds.

Let us see the steps

Step 1: Assume the base as 80

Step 2: Multiply the base by 5

Step 3:Multiply the unit place digit by 5

Step 4:Add the results obtained in step 2 and step 3 to get

Now lets consider a few examples to understand better

Example 1:82 x 5 = ?

Step 1:We assume the base as 80.

Step 2:Multiplying the base by 5
We get 80 x 5 = 400

Step 3:Multiplying the unit place digit by 5
We get 2 x 5 =10

Step 4:Adding results obtained in step 2 and step 3
We get 400 + 10 = 410

Ans 82 x 5 =410

Example 2:87 x 5 = ?

Step 1:We assume the base as 80.

Step 2:Multiplying the base by 5
We get 80 x 5 = 400

Step 3:Multiplying the unit place digit by 5
We get 7 x 5 = 35

Step 4:Adding results obtained in step 2 and step 3
We get 400 + 35 = 435

Ans 87 x 5 =435