用简便方法计算9.9x0.39

2025-06-23 08:55:11
推荐回答(1个)
回答1:

用简便方法计算9.9x0.39
算9.9x0.39
=0.39*(10-0.1)
=0.39*10-0.39*0.1
=3.9-0.039
=3.561