In the previous post we learnt how to multiply any number from 60 to 69 by 5 in seconds.Today we are going to learn another amazing trick to multiply any number from 70 to 79 by 5 in seconds.
Step 1: Assume the base as 70
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 1:73 x 5 = ?
Step 1:We assume the base as 70.
Step 2:Multiplying the base by 5
We get 70 x 5 = 350
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 350 + 15 = 365
Ans 73 x 5 =365
Example 2:79 x 5 = ?
Step 1:We assume the base as 70.
Step 2:Multiplying the base by 5
We get 70 x 5 = 350
Step 3:Multiplying the unit place digit by 5
We get 9 x 5 = 45
Step 4:Adding results obtained in step 2 and step 3
We get 350 + 45 = 395
Ans 79 x 5 =395