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71+72+68+69+74

来源:学生作业帮 编辑:神马作文网作业帮 分类:数学作业 时间:2024/11/12 23:26:34
71+72+68+69+74
2×23×125×4
125×56
3579×101
140×299
34×103-59×34+56×34.
71+72+68+69+74
(1)71+72+68+69+74,
=(71+69)+(72+68)+74,
=140+140+74,
=280+74,
=354;
(2)2×23×125×4,
=(2×4×125)×23,
=1000×23,
=23000;
(3)125×56,
=125×(8×7),
=(125×8)×7,
=1000×7,
=7000;
(4)3579×101,
=3579×(100+1),
=3579×100+3579×1,
=357900+3579,
=361479;
(5)140×299,
=140×(300-1),
=140×300-140×1,
=42000-140,
=41860;
(6)34×103-59×34+56×34,
=34×(103-59+56),
=34×100,
=3400.