(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。
((1+6)+(7-4))=10
((1+6)-(4-7))=10
((1+7)+(6-4))=10
((1+7)-(4-6))=10
((1-4)+(6+7))=10
((6+(1+7))-4)=10
((6+7)+(1-4))=10
((6+7)-(4-1))=10
((6-4)+(1+7))=10
((7+(1+6))-4)=10
((7-4)+(1+6))=10
(1+((6+7)-4))=10
(1+(6+(7-4)))=10
(1+(6-(4-7)))=10
(1+(7+(6-4)))=10
(1+(7-(4-6)))=10
(1-((4-6)-7))=10
(1-((4-7)-6))=10
(1-(4-(6+7)))=10
(6+((1+7)-4))=10
(6+(1+(7-4)))=10
(6+(1-(4-7)))=10
(6+(7+(1-4)))=10
(6+(7-(4-1)))=10
(6-((4-1)-7))=10
(6-((4-7)-1))=10
(6-(4-(1+7)))=10
(7+((1+6)-4))=10
(7+(1+(6-4)))=10
(7+(1-(4-6)))=10
(7+(6+(1-4)))=10
(7+(6-(4-1)))=10
(7-((4-1)-6))=10
(7-((4-6)-1))=10
(7-(4-(1+6)))=10