小数巧算3.1×0.17 3.4×0.31 5.1×0.69怎么做

2025-03-29 01:17:22
推荐回答(1个)
回答1:

=3.1×0.17+3.1×0.34+0.51×6.9
=3.1×(0.17+0.34)+6.9×0.51
=3.1×0.51+6.9×0.51
=(3.1+6.9)×0.51
=10×0.51
=5.1