（ただし１と２を合せて１２のような使い方は出来ません。）
65個の解法が見つかりました。
(((2+9)÷1)-1)=10
((1×(2+9))-1)=10
((1×2)+(9-1))=10
((1×2)-(1-9))=10
((1×9)+(2-1))=10
((1×9)-(1-2))=10
((1+9)×(2-1))=10
((1+9)÷(2-1))=10
((2+(1×9))-1)=10
((2+(9-1))÷1)=10
((2+(9÷1))-1)=10
((2+9)-(1×1))=10
((2+9)-(1÷1))=10
((2-(1-9))÷1)=10
((2-1)×(1+9))=10
((2-1)+(1×9))=10
((2-1)+(9÷1))=10
((2÷1)+(9-1))=10
((2÷1)-(1-9))=10
((9+(1×2))-1)=10
((9+(2-1))÷1)=10
((9+(2÷1))-1)=10
((9-(1-2))÷1)=10
((9-1)+(1×2))=10
((9-1)+(2÷1))=10
((9÷1)+(2-1))=10
((9÷1)-(1-2))=10
(1×((2+9)-1))=10
(1×(2+(9-1)))=10
(1×(2-(1-9)))=10
(1×(9+(2-1)))=10
(1×(9-(1-2)))=10
(1+(9×(2-1)))=10
(1+(9÷(2-1)))=10
(1-(9×(1-2)))=10
(1-(9÷(1-2)))=10
(2+((1×9)-1))=10
(2+((9-1)÷1))=10
(2+((9÷1)-1))=10
(2+(1×(9-1)))=10
(2+(9-(1×1)))=10
(2+(9-(1÷1)))=10
(2-((1×1)-9))=10
(2-((1-9)÷1))=10
(2-((1÷1)-9))=10
(2-(1×(1-9)))=10
(2-(1-(1×9)))=10
(2-(1-(9÷1)))=10
(9+((1×2)-1))=10
(9+((1+1)÷2))=10
(9+((2-1)÷1))=10
(9+((2÷1)-1))=10
(9+(1×(2-1)))=10
(9+(1÷(2-1)))=10
(9+(2-(1×1)))=10
(9+(2-(1÷1)))=10
(9+(2÷(1+1)))=10
(9-((1×1)-2))=10
(9-((1-2)÷1))=10
(9-((1÷1)-2))=10
(9-(1×(1-2)))=10
(9-(1-(1×2)))=10
(9-(1-(2÷1)))=10
(9-(1÷(1-2)))=10