MBBS / ENGG: Practice Entrance Rehearsal  tests online 
 


Example 1 : 

Finding Square of a number ending with 5
To find the square of 75
Do the following
Multiply 5 by 5 and put 25 as your right part of answer. 
Multiply 7 with the next higher digit ie (7+1)=8 gives
56 as the left part of the answer, Answer is 5625

Example 2

Calculate 43 X 47 
The answer is 2021 Same theory worked here too.
The above 'rule' works when you multiply 2 numbers with units digits add up
to 10 and tenth place same 

Example 3 : 52 X 58 = 3016 How long this take ?

Example 4: Multiply 52 X 11 
Answer is 572 
Write down the number being multiplied and put the total of the digits between 2 digits
52 X 11 is [ 5 and 5+2=7 and 2 ] , answer is 572 

Example 5: Can you find the following within less than a minute?

a) 1001/13 ?

b) 1/19 ?

 


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