Mutiply 185 by 215.

Explanation

Step 1: 215 - 185 = 30 (here 30 is an even number)
Step 2:`30/2=15`
Step 3:185 + 15 = 215 - 15 = 200
Step 4:`(200)^2 -(15)^2` = 40000 - 225 = 39775