Multiplying two numbers together in your mind when
they are in the same series & the last two digits
add up to 10: For example: 73 X 77; 46 x 44;
32 X 38; etc.
Increase one first digit by one & then
multiple the first two digits together, that equally the first two digits are the answer;
Multiple last two digits together, that equals last two digits of the answer.
Example: 82 x 88 - increase an 8 by one (=9);
8 x 9 = 72 (first two digits of answer). Multiple
2 x 8 = 16.(last two digits of answer.)
Answer: 82 x 88 = 7,216
Try 63 x 67; 55 x 55; 31 x 39
(Hint 1 x 9 = 09.)