(ただし1と2を合せて12のような使い方は出来ません。)
40個の解法が見つかりました。
(((8+9)-4)-3)=10
((3+9)-(8÷4))=10
((8+(9-3))-4)=10
((8+(9-4))-3)=10
((8+9)-(3+4))=10
((8-(3-9))-4)=10
((8-(4-9))-3)=10
((8-3)+(9-4))=10
((8-3)-(4-9))=10
((8-4)+(9-3))=10
((8-4)-(3-9))=10
((9+(8-3))-4)=10
((9+(8-4))-3)=10
((9-(3-8))-4)=10
((9-(4-8))-3)=10
((9-3)+(8-4))=10
((9-3)-(4-8))=10
((9-4)+(8-3))=10
((9-4)-(3-8))=10
(3+(9-(8÷4)))=10
(3-((8÷4)-9))=10
(8+((9-3)-4))=10
(8+((9-4)-3))=10
(8+(9-(3+4)))=10
(8-((3+4)-9))=10
(8-(3+(4-9)))=10
(8-(3-(9-4)))=10
(8-(4+(3-9)))=10
(8-(4-(9-3)))=10
(9+((8-3)-4))=10
(9+((8-4)-3))=10
(9+(3-(8÷4)))=10
(9+(8-(3+4)))=10
(9-((3+4)-8))=10
(9-((8÷4)-3))=10
(9-(3+(4-8)))=10
(9-(3-(8-4)))=10
(9-(4+(3-8)))=10
(9-(4-(8-3)))=10