作业帮 > 数学 > 作业

脱式计算.51.8-4.8×(2.03-0.18)12-1.25×635.4×0.29-0.29×25.4 &

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/23 18:32:52
脱式计算.
51.8-4.8×(2.03-0.18)
12-1.25×6
35.4×0.29-0.29×25.4           
48×0.69+3.1×4.8.
(1)51.8-4.8×(2.03-0.18),
=51.8-4.8×1.85,
=51.8-8.88,
=42.92;
(2)12-1.25×6,
=12-7.5,
=4.5;
(3)35.4×0.29-0.29×25.4,
=(35.4-25.4)×0.29,
=10×0.29,
=2.9;
(4)48×0.69+3.1×4.8,
=4.8×6.9+3.1×4.8,
=(6.9+3.1)×4.8,
=10×4.8,
=48.
再问: 怎么0.69突然变成6.9?请写详细点。