\(99^2=\left(100-1\right).100-\left(100-1\right).1\)
\(=100^2-100-100+1\)
\(=100^2-200+1\)
\(=10000-199\)
\(=9801\)
\(99^2=\left(100-1\right)^2=100^2-2.100.1+1^2=10000-200+1=90801\)
\(101^2=\left(100+1\right)^2=100^2+2.100.1+1^2=10000+200+1=10201\)
992=(100-1)2=1002-2.100.1+12=10000-200+1=9801.
1012=(100+1)2=1002+2.100.1+12=10000+200+1=10201.