Mental Calculation of n^2 Base 50

n^2 = ((n-50) + 25)x 100+(n-50)^2

From

n^2 = (n-50)^2 + 100n - 50^2 <<< (n^2 - 100n + 50^2) + 100n - 50^2

example

55^2 = ((5 + 25 ) x 100 = 3000) + ( 5 x 5 = 25) = 3025

57^2 = ((7 + 25) x 100 = 3200) + ( 7 x 7 = 49) = 3249

47^2 = ((-3 + 25) x 100 = 2200) + (-3 x -3 = 9) = 2209

61^2 = ((11 + 25) x 100 = 3600) + (11 x 11 = 121) = 3721