（ただし１と２を合せて１２のような使い方は出来ません。）
61個の解法が見つかりました。
((1+(2+9))-2)=10
((1+2)+(9-2))=10
((1+2)-(2-9))=10
((1+9)×(2÷2))=10
((1+9)+(2-2))=10
((1+9)-(2-2))=10
((1+9)÷(2÷2))=10
((1-2)+(2+9))=10
((2×(1+9))÷2)=10
((2+(1+9))-2)=10
((2+9)+(1-2))=10
((2+9)-(2-1))=10
((2-2)+(1+9))=10
((2÷2)×(1+9))=10
((2÷2)+(1×9))=10
((2÷2)+(9÷1))=10
((9+(1+2))-2)=10
((9+(2÷2))÷1)=10
((9-2)+(1+2))=10
((9÷1)+(2÷2))=10
(1×(9+(2÷2)))=10
(1+((2×9)÷2))=10
(1+((2+9)-2))=10
(1+(2×(9÷2)))=10
(1+(2+(9-2)))=10
(1+(2-(2-9)))=10
(1+(2÷(2÷9)))=10
(1+(9×(2÷2)))=10
(1+(9+(2-2)))=10
(1+(9-(2-2)))=10
(1+(9÷(2÷2)))=10
(1-((2-2)-9))=10
(1-((2-9)-2))=10
(1-(2-(2+9)))=10
(2×((1+9)÷2))=10
(2+((1+9)-2))=10
(2+(1+(9-2)))=10
(2+(1-(2-9)))=10
(2+(9+(1-2)))=10
(2+(9-(2-1)))=10
(2-((2-1)-9))=10
(2-((2-9)-1))=10
(2-(2-(1+9)))=10
(2÷(2÷(1+9)))=10
(9+((1×2)÷2))=10
(9+((1+2)-2))=10
(9+((2÷1)÷2))=10
(9+((2÷2)÷1))=10
(9+(1×(2÷2)))=10
(9+(1+(2-2)))=10
(9+(1-(2-2)))=10
(9+(1÷(2÷2)))=10
(9+(2×(1÷2)))=10
(9+(2+(1-2)))=10
(9+(2-(2-1)))=10
(9+(2÷(1×2)))=10
(9+(2÷(2÷1)))=10
(9-((2-1)-2))=10
(9-((2-2)-1))=10
(9-(2-(1+2)))=10