（ただし１と２を合せて１２のような使い方は出来ません。）
36個の解法が見つかりました。
(((6+9)-4)-1)=10
((6+(9-1))-4)=10
((6+(9-4))-1)=10
((6+9)-(1+4))=10
((6-(1-9))-4)=10
((6-(4-9))-1)=10
((6-1)+(9-4))=10
((6-1)-(4-9))=10
((6-4)+(9-1))=10
((6-4)-(1-9))=10
((9+(6-1))-4)=10
((9+(6-4))-1)=10
((9-(1-6))-4)=10
((9-(4-6))-1)=10
((9-1)+(6-4))=10
((9-1)-(4-6))=10
((9-4)+(6-1))=10
((9-4)-(1-6))=10
(4×(1+(9÷6)))=10
(6+((9-1)-4))=10
(6+((9-4)-1))=10
(6+(9-(1+4)))=10
(6-((1+4)-9))=10
(6-(1+(4-9)))=10
(6-(1-(9-4)))=10
(6-(4+(1-9)))=10
(6-(4-(9-1)))=10
(9+((6-1)-4))=10
(9+((6-4)-1))=10
(9+(6-(1+4)))=10
(9-((1+4)-6))=10
(9-(1+(4-6)))=10
(9-(1-(6-4)))=10
(9-(4+(1-6)))=10
(9-(4-(6-1)))=10