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There are basically two methods of multiplication. Those are
- Nikhilam Method
- Urdhva Tiryak Method
In addition of these, there are certain shortcuts in some special cases. In this post we shall discuss some special cases. From our next post we shall discuss nikhilam method.
Concept 1 :
Product of two numbers when the digits in the unit's place are 5's and the digits in the Ten's place are same, in other words square of a number in which the digit in the unit's place is 5 :
Examples :
1. Find 35 x 35
Solution :
Step 1 : Here, in this case first we should multiply 5 by 5
5x5 = 25
Step 2 : Observe that, 3's are there in Tense place. We should increase one of the 3's by 1 then we get 4, we should multiply 4 by 3 then we get 12. So, the required answer is 1225
2. Find 115x115
Solution :
Step 1 : Here, in this case first we should multiply 5 by 5
5x5 = 25
Step 2 : Observe that, 11's are there in Tense place. We should increase one of the 11's by 1 then we get 12, we should multiply 11 by 12
Note : Here we can get 11x12 easily, as we know 112 is 121 and then we should add 11 to 121 then we get 132
so 115 x 115 = 13225
Concept 2 :
a) Product of two numbers when the sum of the digits in the unit's place is 10 and the digits in the Ten's place and hundred's place are the same.
Example :
124 x 126 = 15624
Step 1 : First by multiplying the digits in the Unit's place we get 24
Step 2 : We should write the product of 12 & 13 to the left of 24
124 x 126 = 15624
(we know that 122 is 144 and then we should add 12 to 144 to get 12x13 = 156)
'It may be noted that the product of any two numbers irrespective of the number of digits satisfying the above condition can be found in the same way'.
b) Product of two big numbers satisfying the above condition
Example : 353 x 357
Step 1 : First by multiplying the digits in the one's place we get 21
Step 2 : We should write the product of 35 & 36 to the left of 21
353x357 = 126021
Note : Here we can get 35 x 36 = 1260 as we know 352 is 1225 and then, we should add 35 to 1225 to get 35 x 36 = 1260
Important Points to Note :
- There are basically two methods of multiplication, Nikhilam Method & Urdhva Tiryak Method. In addition to these there are certain shortcuts in some specific cases.
- When we have to find the square of a number with 5 in the unit's place we have to multiply 5 by 5 to get the right part of the answer. The left part of the answer can be obtained by multiplying the other part of the number with the next number.
- When we have to find the product of two numbers with sum of the digits in unit's place 10, and when the digits in the other places are same, we have to multiply the digits in the unit's place to get the right side of the answer. To obtain the left side of the answer we have to multiply the other part of the number with the next number.
Now lets do some exercises (answers will be posted in tomorrow's lesson)
- 65x65
- 85x85
- 95x95
- 75x75
- 55x55
- 125x125
- 135x135
- 145x145
- 165x165
- 105x105
- 175x175
- 155x155
- 253x257
- 354x356
- 459x451
- 652x658
- 857x853
- 959x951
Answers to yesterday's Subtraction Exercises
- 0146
- 0176
- 0226
- 0033
- 0327
- 3224
- 3226
- 0654
- 4944
- 4415
About The Author
Rupali Shete (M.Sc., M.Phil., Ph.D) is a gold medalist from Osmania University (Hyderabad), one of the working members of Rananujan Mathematics Academy and Institute of Scientific Research on Vedas (ISERVE), Currently working in University of Pune.
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hello sir/ mam
ReplyDeleteare you having any idea of number of students shortlisted for ibps po 3 interview??
near about 40-42 thousand
Deleteso it means a candidate who has scored a little low in online exam but able to score medium to high in the interview is having chances of getting job or no matter how the interview will go , he will get no job bcoz of less marks in online exam?
Deletehi sir
ReplyDeletei want to know the syllabus for ibps I.T specilist officer so plz let me know sir plz provide the info as soon as possible
answer for question no 8 . in subtraction for 6213 - 5469 is 744 mam not 654 for ques 8. please correct it.
ReplyDeleteqes 9 answer is also wrong mam here. its 4554 not 4944. i need to check my calculator for answers now. please correct it..
ReplyDelete43* 77 what is the Answer?
ReplyDelete