99.9x7.78十33.3x6.66怎么简算

问题描述:

99.9x7.78十33.3x6.66怎么简算

原式=33.3x3x7.78+33.3x6.66
=33.3x(3x7.78+6.66)
=33.3x(23.34+6.66)
=33.3x30
=999