(ただし1と2を合せて12のような使い方は出来ません。)
32個の解法が見つかりました。
((4+(5+5))-4)=10
((4+5)+(5-4))=10
((4+5)-(4-5))=10
((4-4)+(5+5))=10
((4÷4)×(5+5))=10
((5+(4+5))-4)=10
((5+5)×(4÷4))=10
((5+5)+(4-4))=10
((5+5)-(4-4))=10
((5+5)÷(4÷4))=10
((5-4)+(4+5))=10
(4×((5+5)÷4))=10
(4+((5+5)-4))=10
(4+(5+(5-4)))=10
(4+(5-(4-5)))=10
(4-((4-5)-5))=10
(4-(4-(5+5)))=10
(4÷(4÷(5+5)))=10
(5+((4×5)÷4))=10
(5+((4+5)-4))=10
(5+(4×(5÷4)))=10
(5+(4+(5-4)))=10
(5+(4-(4-5)))=10
(5+(4÷(4÷5)))=10
(5+(5×(4÷4)))=10
(5+(5+(4-4)))=10
(5+(5-(4-4)))=10
(5+(5÷(4÷4)))=10
(5-((4-4)-5))=10
(5-((4-5)-4))=10
(5-(4-(4+5)))=10