Question

Calculate mentally using one of the techniques: easy combinations, making adjustments, or working from left to right. Estimation is not an option. Write down a sequence of numbers indicating intermediate steps in your thought process.

99 x 53

Answer 1

100*53

Answer 2

then subtract 53

Answer 3

5300-53=5247

Answer 4

Now, why does it make any sense at all to post a problem that starts, "calculate mentally"?