In the previous post we learnt how to multiply any number from 80 to 89 by 5 in seconds.Today we are going to learn another cool trick to multiply any number from 90 to 99 by 5 in seconds.
Let us see the steps
Step 1: Assume the base as 90
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
final answer.
Now lets consider a few examples to understand better
Example 1:93 x 5 = ?
Step 1:We assume the base as 90.
Step 2:Multiplying the base by 5
We get 90 x 5 = 450
Step 3:Multiplying the unit place digit by 5
We get 3 x 5 =15
Step 4:Adding results obtained in step 2 and step 3
We get 450 + 15 = 465
Ans 93 x 5 =465
Example 2:98 x 5 = ?
Step 1:We assume the base as 90.
Step 2:Multiplying the base by 5
We get 90 x 5 = 450
Step 3:Multiplying the unit place digit by 5
We get 8 x 5 = 40
Step 4:Adding results obtained in step 2 and step 3
We get 450 + 40 = 490
Ans 98 x 5 =490