FrontMultiplying two digit numbers (less than 100 and greater or equal to 80) easier
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- Engr_Joseph
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Engr_Joseph Sat 10 Dec 2016, 9:25 am
Making multiplication easier:
*Multiplying two digit numbers (less than 100 and greater or equal to 80) with each other:
Example:- 95 x 97
Steps:
1) Find the difference of each number from 100:
95 x 97
5 3
2) Cross Subtract the difference
(95-3)=(97-5)=92 => This is the first part of the answer
3) Multiply the differences
5 x 3 = 15 => This is the last part of the answer which will be added behind
THUS, 95 x 97 = 9215
*Multiplying three digit numbers
(greater than 100 and less than or equal to 120) with each other:
Example:- 107 x 104
Steps: 1) Find the difference of each number from 100:
107 x 104
7 4
2) Cross add the difference
(107+4)=(104+7)=111 => This is the first part of the answer
3) Multiply the differences:
7x4=28 => This is the last part of the answer
THUS,
107x104= 11128
*Multiplying two digit numbers (less than 100 and greater or equal to 80) with each other:
Example:- 95 x 97
Steps:
1) Find the difference of each number from 100:
95 x 97
5 3
2) Cross Subtract the difference
(95-3)=(97-5)=92 => This is the first part of the answer
3) Multiply the differences
5 x 3 = 15 => This is the last part of the answer which will be added behind
THUS, 95 x 97 = 9215
*Multiplying three digit numbers
(greater than 100 and less than or equal to 120) with each other:
Example:- 107 x 104
Steps: 1) Find the difference of each number from 100:
107 x 104
7 4
2) Cross add the difference
(107+4)=(104+7)=111 => This is the first part of the answer
3) Multiply the differences:
7x4=28 => This is the last part of the answer
THUS,
107x104= 11128
Last edited by Engineer_Joseph on Sat 10 Dec 2016, 10:03 am; edited 1 time in total
- Engr_JosephLv2: Member
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Posts : 73 Posts Liked : 38
Engr_Joseph Sat 10 Dec 2016, 9:33 am
If the second part of the answer is more than two digits, add the left most digit to the first part.
Example:
80 × 80
Solution:
80-20 = 60 (this is the first part)
20 × 20 = 400 (00 is the second part, add 4 to the first part 60)
60 + 4 = 64 (this becomes the first part)
Ans.: 6400
Example:
80 × 80
Solution:
80-20 = 60 (this is the first part)
20 × 20 = 400 (00 is the second part, add 4 to the first part 60)
60 + 4 = 64 (this becomes the first part)
Ans.: 6400
- Engr_JosephLv2: Member
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Posts : 73 Posts Liked : 38
Engr_Joseph Sat 10 Dec 2016, 9:36 am
In 3 digit no.
If second part of answer is more than 2 digit than add first part of answer with left most number of second part and join other number with first part
Example
111×119
Solution
111+19=130 (first part)
11×19=209(second part)
Now
130+2=132
Join- 13209
aNswer = 13209
If second part of answer is more than 2 digit than add first part of answer with left most number of second part and join other number with first part
Example
111×119
Solution
111+19=130 (first part)
11×19=209(second part)
Now
130+2=132
Join- 13209
aNswer = 13209
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