Consider all integers from −10 to 5, and square each of them. How many distinct numbers do you get?
(−10)2 = 100
(−9)2 = 81
(−8)2 = 64
(−7)2 = 49
(−6)2 = 36
(−5)2 = 25
(−4)2 = 16
(−3)2 = 9
(−2)2 = 4
(−1)2 = 1
02 = 0
12 = 1
22 = 4
32 = 9
42 = 16
52 = 25
It is observed that there are 11 distinct numbers.