Question

巧算5/17*1/6+5/18*6/17+4/17*5/9

5 1 5 6 4 5
—*— + —*— + —*— =（ ）
17 6 18 17 17 9
5 1 5 6 4 5
—*— + —*— + —*— =（ ）
17 6 18 17 17 9

最好把方法写清楚！

Answer 1

5/17*1/6+5/18*6/17+4/17*5/9
=5/17*1/6+5/17*6/18+5/17*4/9
=5/17*(1/6+1/3+4/9)
=5/17*(3/18+6/18+8/18)
=5/17*17/18
=5/18
即5/18
声明：不是抄上面的

Answer 2

5/17*1/6+5/18*6/17+4/17*5/9
=5/17*1/6+6/18*5/17+5/17*4/9
=5/17*(1/6+6/18+4/9)
=5/17*(3/18+6/18+8/18)
=5/17*17/18
=5/18

Answer 3

(5/17)(1/6)+(5/18)(6/17)+(4/17)(5/9)
=(5/17)(1/6+6/18+4/9)
=(5/17)(17/18)
=5/18

Answer 4

5/17*1/6+5/18*6/17+4/17*5/9
=5/17*1/6+6/18*5/17+5/17*4/9
=5/17*(1/6+6/18+4/9)
=5/17*(3/18+6/18+8/18)
=5/17*17/18
=5/18
运用通分。