9.9+19.9+29.9+39.9+49.9的简便运算是什么?

2025-04-06 00:01:09
推荐回答(1个)
回答1:

9.9+19.9+29.9+39.9+49.9
=10+20+30+40+50-0.1×5
=(10+50)×5÷2-0.5
=150-0.5
=149.5