999.9×999.9+99.99
=99.99×9999+99.99×1 ...........改写
=99.99×(9999+1) ...........乘法的分配律
=99.99×10000
=999900
999.9×999.9+999.9×0.1
=999.9×(999.9+0.1)
=999.9×1000
=99900
解析:本题可用乘法分配律简便计算,则依题意可得,
999.9X999.9十99.99
二99.99X9999十99.99
=99.99X(9999十1)
二99.99X|OOO0
=9999O0
999.9×999.9+99.99
=999.9×(1000-0.1)+99.99
=999.9×1000-999.9×0.1+99.99
=999900-99.99+99.99
=999900
999.9X999.9十99.99
二99.99X9999十99.99
=99.99X(9999十1)
二99.99X|OOO0
=9999O0