Answer:
396
Explanation:
Difference of two squares is breaking down numbers into pieces and using the distributive property to solve. The pieces should be in the form (a-b)(c+d).
Write 22 as (20 + 2) and 18 as (20-2).
(20+2)(20-2) = 400 + 40 - 40 - 4 = 400 - 4 = 396