Trick of the 11s

Try to do these math problems quick.

1x11=
2x11=
3x11=
12x11=
13x11=
25x11=
32x11=
99x11=




Those last few got pretty hard unless if you know the trick of the 11s.

Example: 12 (I will only show the answer in the example.)
x11 (You can only do this with 2 digit numbers)

1. Drop down the 1s digit in the non-11 number, this is the ones digit in the answer. 2
2. Add the two digits together in the non-11 number to get the tens digit. 32
3. Drop down the tens digit to get the digit in the hunderds place. 132

Easy as that!

A few exceptions:

If in step two, the numbers add up to be more then ten, then only use the ones digit and add one to the tens digit in step three.

~Sorry for the bad tutorial. Just type "Multiplying by 11" into google.