(ただし1と2を合せて12のような使い方は出来ません。)
14個の解法が見つかりました。
((9÷9)+(4+5))=10
(4+(5+(9÷9)))=10
(5+(4+(9÷9)))=10
(9+((4+5)÷9))=10
(9+((9-4)÷5))=10
(9+((9-5)÷4))=10
(9+(4÷(9-5)))=10
(9+(5÷(9-4)))=10
(9+(9÷(4+5)))=10
(9-((4-9)÷5))=10
(9-((5-9)÷4))=10
(9-(4÷(5-9)))=10
(9-(5÷(4-9)))=10