Question

5.6乘以3.5这个算式怎么简算？要具体步骤，急急急急急急急急急急急！帮帮吧！？

Answer 1

5.6×3.5
=0.7×8×0.7×5
=(0.7×0.7)×（8×5）
=0.49×40
=4.9×4
=19.6

5.6×3.5
=7×0.8×0.7×5
=（7×0.7）×（0.8×5）
=4.9×4
=（5-0.1）×4
=5×4-0.1×4
=20-0.4
=19.6

Answer 2

5.6×3.5
=（4×1.4）×3.5
=14×1.4
=19.6

（前提是你对完全平方数记得很熟悉！即 11×11=121；12×12=144；13×13=169；14×14=196……………………………………）

Answer 3

5.6×3.5
＝5.6×（5×0.7）
＝5.6×5×0.7
＝2.8×0.7
＝1.96

Answer 4

5.6*3.5=7*0.8*0.5*7=7*0.4*7=49*0.4=(50-1)*0.4=20-0.4=19.6

Answer 5

5.6×3.5=(6-0.4)×3.5=6×3.5-0.4×3.5=21-1.4=19.6