how to calculate sqauare of a number if it ends in 5

52=25
152=225
252=625
352=1225
etc
generalization
a52=a(a+1)52
also tell me how to post superscript and subscript guys
Answer #1
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Moved.
Answer #2
I take it you mean:
5^2 = 25
15^2 = 225
25^2 = 625
35^2 = 1225
etc
generalization
a5^2 = a(a+1)25
——-
Generalization: X5^2 = X(X+1)52 = Y25
—> (10x+5)^2 = 100x^2 + 100x + 25 = 100y + 25
—> 100x^2 + 100x = 100y
—> x^2 + x = y
—> x(x+1) = y