Question

199+99X99用简便方法算，该怎么算

Answer 1

199+99X99用简便方法算
=100+99+99x99
=100+99x（1+99）
=100+99x100
=100+9900
=10000

Answer 2

199+99×99
=100+99+99×99
=99×（99+1）+100
=99×100+100
= （99+1）×100
= 10000