Question

2.78×1.99简便计算(要小学五年级看的懂得，不要复杂）谢谢！还有6.7×20.01要求一样

Answer 1

2.78×1.99=2.78×（2-0.01）=2.78×2-2.78×0.01=5.56-0.278=5.278
6.7×20.01=6.7×（20+0.01）=6.7×20+6.7×0.01=134+0.67=134.67

Answer 2

2.78×1.99
=2.78×2-2.78×0.01
=5.56-0.0278
=5.5322

6.7×20.01
=6.7×20+6.7×0.01
=13.4+0.067
=13.467

Answer 3

2.78×1.99
=2.78×2-2.78×0.01
=5.56-0.0278
=5.5322

6.7×20.01
=6.7×20+6.7×0.01
=13.4+0.067
=13.467

追问

谢谢

追答

6.7×20.01
=6.7×20+6.7×0.01
=134+0.067
=134.067

Answer 4

楼上错！

2.78×1.99

=2.78×（2－0·01）
=2.78×2－2.78×0·01
=5·56－0·0278
=5·5322

6.7×20.01

=6.7×(20＋0·01)
=6.7×20＋6.7×0·01
=134＋0·067
=134·067

不懂的还可以追问！满意请及时采纳！ O(∩_∩)O

追问

谢谢您的提醒，呵呵，差点就错了

Answer 5

2.78X2-2.78X0.01=5.56-0.0278=5.5322