(123456789)2 +
(-123456788)(123456790)
=
123456789_____________
(123456789)2 +
(-123456789 + 1)(123456789 +1)
= 123456789__________
(123456789)2 - (-123456788)2 + (1)2
= 123456789__________
(123456789)2 - (123456788)2 + 1
= 123456789_
0 + 1
= 123456789
