99×99+199
=99×99+100+99
=99x(99+1)+100
=99x100+100
=9900+100
=10000
99×99+100+99等于99×99+1+100等于99×100+100等于9900+100等于10,000
(100-1)×99+99+100=100×99-99×1+99+100=9900+100=10000
99×99+199
=99×(100–1)+199
=99×100-99+199
=9900-99+199
= 9801+199
10000