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简便运算 1.5/7×1/4+1/4×2/7 2.100×(1/5+3/20+4/25) 3.1/5×50+50*4/5

来源:学生作业帮 编辑:作业帮 分类:数学作业 时间:2024/05/10 19:39:08
简便运算 1.5/7×1/4+1/4×2/7 2.100×(1/5+3/20+4/25) 3.1/5×50+50*4/5 4.2/9*8+2/9
1.5/7×1/4+1/4×2/7
=1/4x(5/7+2/7)
=1/4x1
=1/4
2.100×(1/5+3/20+4/25)
=100x1/5+100x3/20+100x4/25
=20+15+16
=51
3.1/5×50+50*4/5
=50x(1/5+4/5)
=50x1
=50
4.2/9*8+2/9
=2/9x(8+1)
=2/9x9
=2