65^2 = 65 × 65 = 4225. This can be calculated directly or using the pattern (a+b)^2 where a=60 and b=5: (60+5)^2 = 3600 + 2(60)(5) + 25 = 3600 + 600 + 25 = 4225. Numbers ending in 5 have a special pattern when squared: the last two digits are always 25, and the prefix is n(n+1) where n is the number formed by the remaining digits.