脱式计算 (能用简便方法的简便计算)①2.07÷2.5÷0.4 ②21.36÷0.8-12.9 ③0.125×32×2.5 ④0.65×201

2024-11-25 09:07:00
推荐回答(1个)
回答1:

①2.07÷2.5÷0.4,
=2.07÷(2.5×0.4),
=2.07÷1,
=2.07;

②21.36÷0.8-12.9,
=26.7-12.9,
=13.8;

③0.125×32×2.5,
=0.125×8×4×2.5,
=(0.125×8)×(4×2.5),
=1×10,
=10;

④0.65×201,
=0.65×(200+1),
=0.65×200+0.65×1,
=130+0.65,
=130.65;

⑤1.2×2.5+8×0.25,
=1.2×2.5+0.8×2.5,
=(1.2+0.8)×2.5,
=2×2.5,
=5;

⑥50.4×19+50.4,
=50.4×(19+1),
=50.4×20,
=1008.