Question

30.2×1.9−1.8怎么简便计算？

Answer 1

=（30+0.2）×1.9-1.8
=30×1.9+0.2×1.9-1.8
=57+0.38-1.8
=55.2+0.38
=55.58

Answer 2

利用乘法分配律，凑整法简便算法。
=30.2乂(2一0.1)一1.8
=30.2X2-30.2乂0.1-1.8
=60.4一3.02一1.8
=60.4一4.82
=60.4一5十0.18
=55.58

Answer 3

30.2×1.9-1.8
=30.2×（2-0.1）-（2-0.1）+0.1
=60.4-3.02-1.8=55.58

Answer 4

30.2×1.9-1.8
=30.2×（2.0-0.1）-1.8
=30.2×2-30.2×0.1-1.8
=69.4-3.02-1.8
=69.4-1.8-3.02
=67.6-3.02
=64.58

Answer 5

30.2×1.9-1.8
=(30+0.2)×1.9-1.8
=57+0.38-1.8
=57.38-1.8
=55.58