Question

脱式计算（能简算的要用简算）12.5×0.4×2.5×89.5×10143.2-1.8

脱式计算（能简算的要用简算）12.5×0.4×2.5×89.5×10143.2-1.8×3-4.64.2×7.8+2.2×4.20.87×3.16+4.6412.5×4.8．

Answer 1

①12.5×0.4×2.5×8
=（12.5×8）×（0.4×2.5）
=100×1
=100

②9.5×101
=9.5×（100+1）
=9.5×100+9.5
=959.5

③43.2-1.8×3-4.6
=43.2-5.4-4.6
=43.2-（5.4+4.6）
=33.2

④4.2×7.8+2.2×4.2
=4.2×（7.8+2.2）
=4.2×10
=42

⑤0.87×3.16+4.64
=2.7492+4.64
=7.3892

⑥12.5×4.8
=12.5×（4+0.8）
=12.5×4+12.5×0.8
=50+10
=60