Hi All,
For some among us it might be a cake walk, those folks who attempted GMAT or CAT etc... but still it is nice and pretty so sending it to you all
Some tips for multiplication with 9, 11, 12, 13
with 9: -
Place 0 in right side of the number, then subtract the actual number with this. for example -
2345 * 9 = ?
step 1 - place 0 at right - 23450
step 2 - Subtract actual number - 2345
-----------
21105
With - 11: -
ex: - 4987 * 11 = ?
step 1 - place 0 at left of the digit. like 04987 in our case.
step 2- multiply the right most digits of both number i.e. (7* 1) if carry comes then carry over it for the next term .
04987
11
--------
54857
step 3- now add the ten digit number with unit digit number (8+7=15) write 5 and carry over 1.
step 4 - now add hundred digit number with ten digit number (9+8=17 +1 (carry over from previous step)= 1
similarly proceed up to left most digit
so we get 54857
With 12 : -
it is similar to the method used for 11.
only difference is in this we have to multiply with 2 then add with the previous digit .
for example :- 4987 * 12 = ?
04987 step 1 - placed 0 in left most.
12
----------------
59844 step2 - 7*2 = 14 , write 4 and carry over 1
step3 - 8*2+ 7=23 + 1 = 24 , write 4 and carry over 2.
step 4- 9*2 +8 = 26, + 2=28. write 8 , 2 carry over.
step5 - 4*2+9=17+2=19, write 9 and carry on 1
step6 - 0*2 + 4 =4+1=5
With 13 - it is similar to 12 but instead of multiplying with 2 here we have to pultiply it with 3.
Enjoyable, EASY??????????????
Thanks
Bala
From India, Madras
For some among us it might be a cake walk, those folks who attempted GMAT or CAT etc... but still it is nice and pretty so sending it to you all
Some tips for multiplication with 9, 11, 12, 13
with 9: -
Place 0 in right side of the number, then subtract the actual number with this. for example -
2345 * 9 = ?
step 1 - place 0 at right - 23450
step 2 - Subtract actual number - 2345
-----------
21105
With - 11: -
ex: - 4987 * 11 = ?
step 1 - place 0 at left of the digit. like 04987 in our case.
step 2- multiply the right most digits of both number i.e. (7* 1) if carry comes then carry over it for the next term .
04987
11
--------
54857
step 3- now add the ten digit number with unit digit number (8+7=15) write 5 and carry over 1.
step 4 - now add hundred digit number with ten digit number (9+8=17 +1 (carry over from previous step)= 1
similarly proceed up to left most digit
so we get 54857
With 12 : -
it is similar to the method used for 11.
only difference is in this we have to multiply with 2 then add with the previous digit .
for example :- 4987 * 12 = ?
04987 step 1 - placed 0 in left most.
12
----------------
59844 step2 - 7*2 = 14 , write 4 and carry over 1
step3 - 8*2+ 7=23 + 1 = 24 , write 4 and carry over 2.
step 4- 9*2 +8 = 26, + 2=28. write 8 , 2 carry over.
step5 - 4*2+9=17+2=19, write 9 and carry on 1
step6 - 0*2 + 4 =4+1=5
With 13 - it is similar to 12 but instead of multiplying with 2 here we have to pultiply it with 3.
Enjoyable, EASY??????????????
Thanks
Bala
From India, Madras
Hi Bala,
One tips from my side...
1) 5x5 = 25
2) 15x15 = (1x(1+1)25) = (1x2)25 = 225
3) 25x25 = (2x(2+1)25) = (2x3)25 = 625
4) 35x35 = (3x(3+1)25) = (3x4)25 = 1225
5) 45x45 = (4x(4+1)25) = (4x5)25 = 2025
etc.......
Now every body will come to know how its easy to multify like 5x5, 15x15, 25x25, 35x35, 45x45, 55x55, 65x65.........
Regards
Sidhu
From India, Bangalore
One tips from my side...
1) 5x5 = 25
2) 15x15 = (1x(1+1)25) = (1x2)25 = 225
3) 25x25 = (2x(2+1)25) = (2x3)25 = 625
4) 35x35 = (3x(3+1)25) = (3x4)25 = 1225
5) 45x45 = (4x(4+1)25) = (4x5)25 = 2025
etc.......
Now every body will come to know how its easy to multify like 5x5, 15x15, 25x25, 35x35, 45x45, 55x55, 65x65.........
Regards
Sidhu
From India, Bangalore
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