Question

2.8×5.6+3点4×2又五分之四加280%等于几简便计算？

Answer 1

2.8×5.6+3.4×2又（4/5）+280%
=2.8×5.6+3.4×2又（4/5）+2.8
=2.8×5.6+3.4×2.8+2.8
=2.8×（5.6+3.4+1）
=28

Answer 2

此题采用提取公因数方法进行简算，原式=2.8*5.6+3.4*2.8+2.8=2.8*（5.6+3.4+1）=2.8*10=28