Multiplication Verification Method

Will start with an example to make the explanation simpler,

987x987=974 169

We need to calculate four parameters A, B, C, D.

A=>Add all the numbers in 987 till you get a single digit. (6)
B=> Add all the numbers in 987 till you get a single digit. (6)
Here A=B since both numbers are same. (6)
C=AXB (added to a single digit) (6X6 = 36 => 3+6=9)
We got A=B=6 and C=9

Now D=add all the numbers in the answer to a single digit.

D=9+7+4+1+6+9=36=>3+6=9
D=9

C=D Hence the answer is correct.

This procedure may seem hard but on practice it looks to be simpler especially when large numbers are used and where re-checking seems to be difficult. Can be taught to children, so they can check their answers in exams…