5.6乘以3.5这个算式怎么简算?要具体步骤,

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5.6乘以3.5这个算式怎么简算?要具体步骤,

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

5.6乘以3.5这个算式怎么简算?要具体步骤,
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

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

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

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……………………………………)

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