（ただし１と２を合せて１２のような使い方は出来ません。）
48個の解法が見つかりました。
(((7+9)-4)-2)=10
((2×4)+(9-7))=10
((2×4)-(7-9))=10
((4×7)-(2×9))=10
((4+(7+9))÷2)=10
((7+(4+9))÷2)=10
((7+(9-2))-4)=10
((7+(9-4))-2)=10
((7+9)-(2+4))=10
((7-(2-9))-4)=10
((7-(4-9))-2)=10
((7-2)+(9-4))=10
((7-2)-(4-9))=10
((7-4)+(9-2))=10
((7-4)-(2-9))=10
((9+(2×4))-7)=10
((9+(4+7))÷2)=10
((9+(7-2))-4)=10
((9+(7-4))-2)=10
((9-(2-7))-4)=10
((9-(4-7))-2)=10
((9-2)+(7-4))=10
((9-2)-(4-7))=10
((9-4)+(7-2))=10
((9-4)-(2-7))=10
((9-7)+(2×4))=10
(2+(4×(9-7)))=10
(2-(4×(7-9)))=10
(4×(7-(9÷2)))=10
(7+((9-2)-4))=10
(7+((9-4)-2))=10
(7+(9-(2+4)))=10
(7-((2+4)-9))=10
(7-(2+(4-9)))=10
(7-(2-(9-4)))=10
(7-(4+(2-9)))=10
(7-(4-(9-2)))=10
(9+((2×4)-7))=10
(9+((7-2)-4))=10
(9+((7-4)-2))=10
(9+(7-(2+4)))=10
(9-((2+4)-7))=10
(9-(2+(4-7)))=10
(9-(2-(7-4)))=10
(9-(4+(2-7)))=10
(9-(4-(7-2)))=10
(9-(7-(2×4)))=10