Multiplication by 11 is simple. For a 2-digit number just add the two digits of the number multiplied by 11 and place the sum in between that number carrying any ones overs.

19 x 11

1 + 9 = 10 (you will carry the 1 )

take the first number (19) and spread out the 1 and 9

1 ____ 9

put the sum in the middle using only the last digit. Carry the ones, if any over.

1 9

1 0

-----------

2 0 9

Answer: 209

Easy. No calculator needed!

"whizkid"...okay... >_<