Aptitude - Numbers - Discussion

5+3+5+8=21(2+1=3).
And 5+1=6 (6),
And then 6+3 = 9,
and = 2+7+3+2+5+8,
= 27.
2+7 = 9.

=> 5358 * (100/2 +1).
=> (5358* 100 )/2 + 5358.
=> 267900 + 5358.
=> 273258.

5 + 3 + 5 + 8 = 21(2+1=3).
And 5 + 1 = 6 (6),
And then 6 + 3 = 9,
and = 2 + 7 + 3 + 2 + 5 + 8,
= 27.

Then 2 + 7 = 9.

But for option C;
2 + 7 + 3 + 3 + 4 + 8.
And the addition will be 9.

I think, Cris Cross method is much simpler to all, as we start getting values from unit place so we dont have to find all the digits. Find one check the option, second number check the option, and so on..
5358
*0051
--------
(AL MULTIPICATION ARE DONE W.R.T LOWER NUMBER )
1) Unit place = 1*8 = 8 (Observe the option, all have 8 in
unit place, so carry on for next
value.)

2) tens place = (1*5 + 5*8) = 5+40 = 45 = 5
(put 5 in tens pace and 4 is carry for nxt
step if required)
answer till now is 58
(Check the options.....only 2 are with this
digits, so step 3....)

3) hundreds place = (1*3 + 0*8 + 5*5) = 3 + 25 + 4 = 32
(4 is carry from privous step.)
(Again put 2 in 100's pace and 3 as carry
for nxt step.)
answer till this stage is 258
(check the options.... only one option
matching this number so no
more calculation)
answer is A.

eg : if digits are abcd * wxyz
1) here (d*z) gives unit place number.
2) (z*c + y*d)gives tens place number.
3) (z*b + x*d + y*c) gives hundred place number.
4) (z*a + w*d + y*d + x*c)gives thousand number.
(OBSERVE THE TRICK)
5) (y*a + w*c + x*b) given nxt number to left.
6) (x*a + w*b) give nxt number.
7) (w*a) gives last number.
(Please note when ever you get CARRY from one STEP please add That Carry to The Step Followed after that step)
e.g: if step 1 results 57 as the answer put 7 at unit place and carry 5 to 2 step, add this five to 2 step result and so on...
if the explanation look wierd or trouble some please google vedic maths, and the name of this method is criss cross method.

5358 x 51 = 5358 x (50 + 1).

= 5358 x 50 + 5358 x 1.

= 5358 x100/2+5358.

= 535800/2+5358.

= 267900+5358.

= 273258.

But why you directly multiply 5352*51?

Follow step by step.

5358 x 51 = 5358 x (50 + 1).
= 5358 x 50 + 5358 x 1
= 267900 + 5358
= 273258.

Use the standard method that your elementary teacher teach you, I think it is much simpler, don't complicate things too much.

5358 * 51.
5358 (5358*1)
26790 (5358*5).
= 273258.

How it possible to multiply 51 by 5358, . ? can you please explain. It will be helpful for my placement.