Respostas

2014-04-16T17:44:25-03:00
180÷[10+2·[20-45÷(13-2×5)]]
180÷[10+2·[20-45÷(13-10)]]
180÷[10+2·[20-45÷3]]
180÷[10+2·[20-15]]
180÷[10+2·5]
180÷[10+10]
180÷20 = 9

Confira ;)
1 5 1
2014-04-16T18:56:37-03:00
180÷[10+2·[20-45÷(13-2×5)]]
180÷[10+2·[20-45÷(13-10)]]
180÷[10+2·[20-45÷3]]
180÷[10+2·[20-15]]
180÷[10+2·5]
180÷[10+10]
180÷20 = 9
1 5 1