Question

二点四乘三点九减三点八怎么样简便运算

Answer 1

2.4x3.9-3.8
=1.4x3.9+0.1
=1.4x4+0.1-0.14
=5.6-0.04
=5.56

Answer 2

2.4×4-＜0.1+3.8＞＝5.7。