multiplication

gaurav200x said:
Please explain the above with elaborate explanation.
Click to expand...


this is a trick to multiply any num.. by 12
sappose u have to multiply 123 by 12
step 1 -write down the first left hand side digite as it is
in this case "1" is the digit
step 2- multiply first left hand side digite "1" by "2" of "12"
u will have 1*2=2 now add the 2nd left hand side digite "2" to it
2+2=4
step 3- multiply 2nd left hand side digite "2" by "2" of "12"
u will have 2*2=4 add 3rd left hand side digite "3" to it
4+3=7
step 4-just multiply 3rd left hand side digite 3 to 2.
3*2=6

so the answer is 1476. there u have it
 
mwm_jsr said:
this is a trick to multiply any num.. by 12
sappose u have to multiply 123 by 12
step 1 -write down the first left hand side digite as it is
in this case "1" is the digit
step 2- multiply first left hand side digite "1" by "2" of "12"
u will have 1*2=2 now add the 2nd left hand side digite "2" to it
2+2=4
step 3- multiply 2nd left hand side digite "2" by "2" of "12"
u will have 2*2=4 add 3rd left hand side digite "3" to it
4+3=7
step 4-just multiply 3rd left hand side digite 3 to 2.
3*2=6

so the answer is 1476. there u have it
Click to expand...
Thanks..... however, it would have been easier to understand the above, if you have not taken 123 but something like 567.

What shall we do if we have a carry?

Please explain the multiplication of 9876 with 12 !!
 
12*98

step 1-9 as it is 9 (9+"2"(from step 2)=11)--->11
step 2-9*2=18 then we add 2nd dig 8-->18 +8=26--->6+"1"(from step 3)-->7
keep the 6 and send thethe 2 to step 1 and add (9+2=11)
step 3-8*2=16--->6,
keep 6 and send "1" to step 2
answer ---1176
 
mwm_jsr said:
12*98

step 1-9 as it is 9 (9+"2"(from step 2)=11)--->11
step 2-9*2=18 then we add 2nd dig 8-->18 +8=26--->6+"1"(from step 3)-->7
keep the 6 and send thethe 2 to step 1 and add (9+2=11)
step 3-8*2=16--->6,
keep 6 and send "1" to step 2
answer ---1176
Click to expand...
Thanks for the explanation, although I personally feel that the method is quite complicated since you would have to add to the previous step the tens digit and hence, in CAT where u get 2-3 seconds to do calculations, such methods will take away a lot of time.

Try to find simpler methods.
 
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