9.9*9.9+1.99=?简便运算
问题描述：
9.9*9.9+1.99=?简便运算
答
(9.9)的平方+1+0.99
(9.9+1)的平方+0.99
=100
答
9.9*9.9+1.99
=9.9*9.9+0.99+1
=0.99(10*9.9+1)+1
=0.99*100+1
=99+1
=100
答
9.9*9.9+1.99=9.9*9.9+9.9*0.1+1=9.9*（9.9+0.1）+1=99+1=100
答
=(10-0.1)^2+1.99
=100-2+0.01+1.99
=100