Question

1.39x6.1+39x13.9用简便方法怎么算？

Answer 1

1.39×6.1+39×13.9
=13.9×0.61+39×13.9
=13.9×(0.61+39)
=13.9×39.61
=550.579
这道题应该是出错了？6.1这里应该是610或者39变成0.39

Answer 2

1.39×61+3.9×13.9
=1.39×61+39×1.39
=1.39×(61+39)
=1.39×100=139