（ただし１と２を合せて１２のような使い方は出来ません。）
52個の解法が見つかりました。
((2×5)×(9÷9))=10
((2×5)+(9-9))=10
((2×5)-(9-9))=10
((2×5)÷(9÷9))=10
((2×9)×(5÷9))=10
((2×9)÷(9÷5))=10
((2÷9)×(5×9))=10
((5×(2×9))÷9)=10
((5×9)×(2÷9))=10
((5×9)÷(9÷2))=10
((5÷9)×(2×9))=10
((9×(2×5))÷9)=10
((9+(2×5))-9)=10
((9-9)+(2×5))=10
((9÷9)×(2×5))=10
(2×((5×9)÷9))=10
(2×((5+9)-9))=10
(2×(5×(9÷9)))=10
(2×(5+(9-9)))=10
(2×(5-(9-9)))=10
(2×(5÷(9÷9)))=10
(2×(9×(5÷9)))=10
(2×(9+(5-9)))=10
(2×(9-(9-5)))=10
(2×(9÷(9÷5)))=10
(2÷((9÷5)÷9))=10
(2÷((9÷9)÷5))=10
(2÷(9÷(5×9)))=10
(5×((2×9)÷9))=10
(5×((2+9)-9))=10
(5×(2×(9÷9)))=10
(5×(2+(9-9)))=10
(5×(2-(9-9)))=10
(5×(2÷(9÷9)))=10
(5×(9×(2÷9)))=10
(5×(9+(2-9)))=10
(5×(9-(9-2)))=10
(5×(9÷(9÷2)))=10
(5÷((9÷2)÷9))=10
(5÷((9÷9)÷2))=10
(5÷(9÷(2×9)))=10
(9×((2×5)÷9))=10
(9×(2×(5÷9)))=10
(9×(2÷(9÷5)))=10
(9×(5×(2÷9)))=10
(9×(5÷(9÷2)))=10
(9+((2×5)-9))=10
(9-(9-(2×5)))=10
(9÷((9÷2)÷5))=10
(9÷((9÷5)÷2))=10
(9÷(9÷(2×5)))=10