For this we can use vertically and crosswise method.
This can be explain using a simple example 9 x 7
For this subtract 9 from 10 and write the result as 9   1
Then same is doing for 7 ie: 7   3

After that write them on two rows a apply crosswise subtraction

ie:    9    1
           \  |
        7    3  
    (7-1) (1x3)  =  63 that is it.
       or
   (9 -3)
    ie:you get first digit by crosswise and 2nd digit by vertical multiplication of the right side


eg:   6 x 7     is       6   4
                                  \
                               7   3 
                               3  (12)    ie 42

Similar way you can do this method for numbers greater than 50 x 50 as shown below

eg:  84 x 96
                For this   84      (100-84)
                               96       (100-96)  

                     ie:       84    16
                                96      4 
                          (84-4)    4x16            ie:  8064
                             or
                        (96-16)   

Similar way you can do the higher numbers also.