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几道简算题41.1/17×4/9+5/17×1/92.1/7×3/4+3/7×1/6+6/7×1/123.5/9×79又

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/23 18:41:52
几道简算题4
1.1/17×4/9+5/17×1/9
2.1/7×3/4+3/7×1/6+6/7×1/12
3.5/9×79又16/17+50×1/9+1/9×5/17
4.5/17×3/8+1/15×7/16+1/15×3又1/2
1.1/17×4/9+5/17×1/9
= 1/17×4/9+1/17×5/9
= 1/17×(4/9+5/9)
= 1/17
2.1/7×3/4+3/7×1/6+6/7×1/12
= 3/7×1/4+3/7×1/6+3/7×1/6
= 3/7×(1/4+1/6+1/6)
= 3/7×7/12
= 1/4
3.5/9×79又16/17+50×1/9+1/9×5/17
= 5/9×(179又16/17+10+1/17)
= 5/9×90
= 50
4.5/17×3/8+1/15×7/16+1/15×3又1/2
= 7/15×3/8+7/15×1/16+7/15×1/2
= 7/15×(3/8+1/16+1/2)
= 7/16