分数四则混合运算练习
1:
(1)2/3x+1/6x=1/4
4/6x+1/6x=1/4
5/6x=1/4
x=3/10
(2) x-7/9x=5/12
2/9x=5/12
x=15/8
(3) 3/5x+20=50
3/5x=30
x=50
2:(1)
2/5×(1/2+1/3)÷4/9
= 2/5×5/6×9/4
= 3/4
(2)
[17/12-(3/4 - 1/6)]÷3/4
= [17/12-7/12]÷3/4
= 5/6×4/3
= 10/9
3: 表面积
1/2×1/5×4+1/5×1/5×2
= 2/5+2/25
= 12/25(平方米)
体积
1/2×1/5×1/5=1/50(立方米)
4: (1) 1/2×2+1/5×5=2(升)=2000(毫升)
答:一共是2000毫升。(2) 1/2×2÷1/5= 5(小盒)
答:相当于5小盒牛奶净含量。
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