In the previous post we learnt how to multiply any number from 10 to 19 by 5 in seconds.Today we are going to learn another cool trick to multiply any number from 20 to 29 by 5 in seconds.
Let us see the steps
Step 1: Assume the base as 20
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
Now lets consider a few examples to understand better
Example 1:21 x 5 = ?
Step 1:We assume the base as 20.
Step 2:Multiplying the base by 5
We get 20 x 5 = 100
Step 3:Multiplying the unit place digit by 5
We get 1 x 5 = 5
Step 4:Adding results obtained in step 2 and step 3
We get 100 + 5 = 105
Ans 21 x 5 = 105
Example 2:26 x 5 = ?
Step 1:We assume the base as 20.
Step 2:Multiplying the base by 5
We get 20 x 5 = 100
Step 3:Multiplying the unit place digit by 5
We get 6 x 5 = 30
Step 4:Adding results obtained in step 2 and step 3
We get 100 + 30 = 130
Ans 26 x 5 = 130