Squaring a two-digit number ending in 5

To find the square of a two-digit number ending in 5, take the first digit, multiply by itself plus one, and then put "25" after it.


Example: To find 652, compute 6 * 7 = 42, then write "4225" as the answer.
Example: To find 252, compute 2 * 3 = 6, then write "625" as the answer.
Note: This only works if the second digit is 5!