（ただし１と２を合せて１２のような使い方は出来ません。）
69個の解法が見つかりました。
(((8+9)÷1)-7)=10
((1×(8+9))-7)=10
((1×8)+(9-7))=10
((1×8)-(7-9))=10
((1×9)+(8-7))=10
((1×9)-(7-8))=10
((1+9)×(8-7))=10
((1+9)÷(8-7))=10
((8+(1×9))-7)=10
((8+(9-7))÷1)=10
((8+(9÷1))-7)=10
((8+9)-(1×7))=10
((8+9)-(7÷1))=10
((8-(7-9))÷1)=10
((8-7)×(1+9))=10
((8-7)+(1×9))=10
((8-7)+(9÷1))=10
((8÷1)+(9-7))=10
((8÷1)-(7-9))=10
((9+(1×8))-7)=10
((9+(8-7))÷1)=10
((9+(8÷1))-7)=10
((9-(7-8))÷1)=10
((9-7)+(1×8))=10
((9-7)+(8÷1))=10
((9÷1)+(8-7))=10
((9÷1)-(7-8))=10
(1×((8+9)-7))=10
(1×(8+(9-7)))=10
(1×(8-(7-9)))=10
(1×(9+(8-7)))=10
(1×(9-(7-8)))=10
(1+(9×(8-7)))=10
(1+(9÷(8-7)))=10
(1-(9×(7-8)))=10
(1-(9÷(7-8)))=10
(8+((1×9)-7))=10
(8+((9-7)÷1))=10
(8+((9÷1)-7))=10
(8+(1×(9-7)))=10
(8+(9-(1×7)))=10
(8+(9-(7÷1)))=10
(8-((1×7)-9))=10
(8-((7-9)÷1))=10
(8-((7÷1)-9))=10
(8-(1×(7-9)))=10
(8-(7-(1×9)))=10
(8-(7-(9÷1)))=10
(9+((1×8)-7))=10
(9+((1+7)÷8))=10
(9+((8-1)÷7))=10
(9+((8-7)÷1))=10
(9+((8÷1)-7))=10
(9+(1×(8-7)))=10
(9+(1÷(8-7)))=10
(9+(7÷(8-1)))=10
(9+(8-(1×7)))=10
(9+(8-(7÷1)))=10
(9+(8÷(1+7)))=10
(9-((1×7)-8))=10
(9-((1-8)÷7))=10
(9-((7-8)÷1))=10
(9-((7÷1)-8))=10
(9-(1×(7-8)))=10
(9-(1÷(7-8)))=10
(9-(7-(1×8)))=10
(9-(7-(8÷1)))=10
(9-(7÷(1-8)))=10