分数乘法的简便运算?
问题描述：
分数乘法的简便运算?
2/9-7/16×2/9
4/5×7/9×5/8
5/6×5/9+5/9×1/6
5/7×16×21/5
答
1,原式=(1-7/16)×2/9
=9/16×2/9
=1/8
2,原式=(4/5×5/8)×7/9
=1/2×7/9
=7/18
3,原式=(5/6+1/6)×5/9
=1×5/9
=5/9
4,原式=(5/7×21/5)×16
=3×16
=48
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