（ただし１と２を合せて１２のような使い方は出来ません。）
51個の解法が見つかりました。
((2×4)-(5-7))=10
((2+(5+7))-4)=10
((2+5)+(7-4))=10
((2+5)-(4-7))=10
((2+7)+(5-4))=10
((2+7)-(4-5))=10
((2-4)+(5+7))=10
((5+(2+7))-4)=10
((5+7)+(2-4))=10
((5+7)-(4-2))=10
((5+7)-(4÷2))=10
((5-4)+(2+7))=10
((7+(2×4))-5)=10
((7+(2+5))-4)=10
((7-4)+(2+5))=10
((7-5)+(2×4))=10
(2+((5+7)-4))=10
(2+(4×(7-5)))=10
(2+(5+(7-4)))=10
(2+(5-(4-7)))=10
(2+(7+(5-4)))=10
(2+(7-(4-5)))=10
(2-((4-5)-7))=10
(2-((4-7)-5))=10
(2-(4×(5-7)))=10
(2-(4-(5+7)))=10
(4+((5+7)÷2))=10
(5+((2+7)-4))=10
(5+(2+(7-4)))=10
(5+(2-(4-7)))=10
(5+(7+(2-4)))=10
(5+(7-(4-2)))=10
(5+(7-(4÷2)))=10
(5-((4-2)-7))=10
(5-((4-7)-2))=10
(5-((4÷2)-7))=10
(5-(4-(2+7)))=10
(5÷(4-(7÷2)))=10
(7+((2×4)-5))=10
(7+((2+5)-4))=10
(7+(2+(5-4)))=10
(7+(2-(4-5)))=10
(7+(5+(2-4)))=10
(7+(5-(4-2)))=10
(7+(5-(4÷2)))=10
(7-((4-2)-5))=10
(7-((4-5)-2))=10
(7-((4÷2)-5))=10
(7-(4-(2+5)))=10
(7-(5-(2×4)))=10