Basics Of Multiplication | Multiplication Tricks | Multiplication of Two Digit Number Having Same Tens Digit and Sum of Unitary Digits is 10

Let us take a look at some pairs of numbers given below.

1) 33 & 37   2)  52 & 58   3) 41 & 49   4) 34 & 36  5) 23 & 27  

If we observe each pair carefully, we will notice that in each pair the digit at tens place are equal & Sum of the digits at ones place is 10.

Some Pairs of numbers have a different Property. 

Here, we are going to discuss "How to find product of two digit numbers where Tens Digits are Equal and Sum of Unitary Digits is Equals to 10 ? "

For Ex. - 41 × 49

Step 1 :- Divide the Result Portion in in 2 parts. 

In left most part we will multiply tens digit by it's successor. (i.e. 4 × 5 = 20)

Step 2 :-  In rightmost part multiply both the digits of ones place. (i.e. 1 × 9 = 9) and if the result is in single digit Put a '0' in front of it. (i.e. 09)

Final Result :- 2009.

For Ex. - 33 × 37

 Step 1 :- Divide the Result Portion in in 2 parts. 

In left most part we will multiply tens digit by it's successor. (i.e. 3 × 4 = 12)

Step 2 :-  In rightmost part multiply both the digits of ones place. (i.e. 3 × 7 = 21) and if the result is in single digit Put a '0' in front of it.

(As you can see the result is in Two digit Hence we don't need to put '0' in front of it.) 

Final Result :- 1221.

Problems For Practice

 1) 91 × 99

2) 84 × 86

3) 67 × 63

4) 59 × 51

5) 47 × 43