Simple Math Trick

This one can be done in your head using the number 11.
Take 11 and multiply it by any 2 digits, and add that 2 digit together and put the answer in between the 2 digit.
Example 1: 11 x 12 = 132.Example 2: 11 x 34 = 374
1+2=3, put the 3 in between the 1 and 2. The same thing applies to any other 2 digits.3+4=7, put the 7 in between the 3 and 4.
For 3 digits, it's a little different but same concept. Add the last 2 digits (right and mid #) together, then add the first 2 digits (left and mid #) and put it in the middle, except replace the middle number with the new answers and keep the first and last digits.
Example 1: 11 x 127 = 1397Example 2: 11 x 255 = 2805
2+7=9 and 1+2=3. Replace the #2 with the 3 and 9 and keep the first and last digits.
For example 2, just remember to carry the remainder and add it to the left answer.5+5=0 (keep the 0 and carry the 1 to the left side) and 2+5=8 (7+1 from the 1 remainder).
Have fun impressing someone, especially your math teacher :)