（ただし１と２を合せて１２のような使い方は出来ません。）
28個の解法が見つかりました。
((5+(9-2))-2)=10
((5+9)-(2×2))=10
((5+9)-(2+2))=10
((5-(2-9))-2)=10
((5-2)+(9-2))=10
((5-2)-(2-9))=10
((9+(5-2))-2)=10
((9-(2-5))-2)=10
((9-2)+(5-2))=10
((9-2)-(2-5))=10
(2+(2×(9-5)))=10
(2-(2×(5-9)))=10
(2÷(2-(9÷5)))=10
(5+((9-2)-2))=10
(5+(9-(2×2)))=10
(5+(9-(2+2)))=10
(5-((2×2)-9))=10
(5-((2+2)-9))=10
(5-(2+(2-9)))=10
(5-(2-(9-2)))=10
(9+((5-2)-2))=10
(9+(5-(2×2)))=10
(9+(5-(2+2)))=10
(9-((2×2)-5))=10
(9-((2+2)-5))=10
(9-(2+(2-5)))=10
(9-(2-(5-2)))=10