Special Multiplication Method

I got this from an email, which I found it very interesting and useful.
Try to calculate 17×18 manually, I mean in your brain.
Does it takes a long time for you to get the answer?

Here is an easy way.

Take the first number(17) add with the unit number of the second number (8).-----(=25)
Multiply the result with 10-------(25×10=250)
Multiply the unit number of the 1st and 2nd number (7×8)---------(56)
Take 250+56=306, and that's your answer.

Example 1:
14×13：
(1)14+3＝17
(2)17×10＝170
(3)4×3＝12
(4)170+12＝182

Example 2:
16×17：
(1)16+7＝23
(2)23×10＝230
(3)6×7＝42
(4)230+42＝272

This method is valid from 11×11 to 19×19.