@gunsnrosesgirl3 Math is about accuracy, not how fast you can calculate.
I assume the girl on the right calculate like this:
9 x 7 = 63. (Take digit with smallest power, 3)
9 x 4 = 36. (Take 6)
Then 97 - 6 = 91 is the first 2 digits
6 x 3 = 18 is the last 2 digits.