vedic maths

25*25 = 625

first step - 5*5 =25
2nd step - 2* next no i.e 3, 2*3 = 6
now the ans 625.


998 * 997 =995006

998 -2     round the number to thousand ie  2 first step
997-3      round the number to thousand ie  3 second step
--------
995006    multiply 2 and 3 write 6 on the right side
-------      your main number is 3digit so you have to add 2 zero to the left side of 6 now it is 006
                 now you minus 998-3 =995
                 ans = 995006