(Exploration) Find all perfect squares from 1 to 500, each of which is a sum of two perfect squares.
The number of perfect squares from 1 to 500 is:
A. 1
B. 16
C. 22
D. 25
Which number must be subtracted from 1786 to make it a perfect square?
Find the least number which must be substracted from 1989 to make it a perfect square. Also the square root of the perfect numbers , so obtained ?