（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+(8+9))-8)=10
((1+8)+(9-8))=10
((1+8)-(8-9))=10
((1+9)×(8÷8))=10
((1+9)+(8-8))=10
((1+9)-(8-8))=10
((1+9)÷(8÷8))=10
((1-8)+(8+9))=10
((8×(1+9))÷8)=10
((8+(1+9))-8)=10
((8+9)+(1-8))=10
((8+9)-(8-1))=10
((8-8)+(1+9))=10
((8÷8)×(1+9))=10
((8÷8)+(1×9))=10
((8÷8)+(9÷1))=10
((9+(1+8))-8)=10
((9+(8÷8))÷1)=10
((9-8)+(1+8))=10
((9÷1)+(8÷8))=10
(1×(9+(8÷8)))=10
(1+((8×9)÷8))=10
(1+((8+9)-8))=10
(1+(8×(9÷8)))=10
(1+(8+(9-8)))=10
(1+(8-(8-9)))=10
(1+(8÷(8÷9)))=10
(1+(9×(8÷8)))=10
(1+(9+(8-8)))=10
(1+(9-(8-8)))=10
(1+(9÷(8÷8)))=10
(1-((8-8)-9))=10
(1-((8-9)-8))=10
(1-(8-(8+9)))=10
(8×((1+9)÷8))=10
(8+((1+9)-8))=10
(8+(1+(9-8)))=10
(8+(1-(8-9)))=10
(8+(9+(1-8)))=10
(8+(9-(8-1)))=10
(8-((8-1)-9))=10
(8-((8-9)-1))=10
(8-(8-(1+9)))=10
(8÷(8÷(1+9)))=10
(9+((1×8)÷8))=10
(9+((1+8)-8))=10
(9+((8÷1)÷8))=10
(9+((8÷8)÷1))=10
(9+(1×(8÷8)))=10
(9+(1+(8-8)))=10
(9+(1-(8-8)))=10
(9+(1÷(8÷8)))=10
(9+(8×(1÷8)))=10
(9+(8+(1-8)))=10
(9+(8-(8-1)))=10
(9+(8÷(1×8)))=10
(9+(8÷(8÷1)))=10
(9-((8-1)-8))=10
(9-((8-8)-1))=10
(9-(8-(1+8)))=10