（ただし１と２を合せて１２のような使い方は出来ません。）
56個の解法が見つかりました。
((2×5)×(7÷7))=10
((2×5)+(7-7))=10
((2×5)-(7-7))=10
((2×5)÷(7÷7))=10
((2×7)×(5÷7))=10
((2×7)÷(7÷5))=10
((2-7)×(5-7))=10
((2÷7)×(5×7))=10
((5×(2×7))÷7)=10
((5×7)×(2÷7))=10
((5×7)÷(7÷2))=10
((5-7)×(2-7))=10
((5÷7)×(2×7))=10
((7×(2×5))÷7)=10
((7+(2×5))-7)=10
((7-2)×(7-5))=10
((7-5)×(7-2))=10
((7-7)+(2×5))=10
((7÷7)×(2×5))=10
(2×((5×7)÷7))=10
(2×((5+7)-7))=10
(2×(5×(7÷7)))=10
(2×(5+(7-7)))=10
(2×(5-(7-7)))=10
(2×(5÷(7÷7)))=10
(2×(7×(5÷7)))=10
(2×(7+(5-7)))=10
(2×(7-(7-5)))=10
(2×(7÷(7÷5)))=10
(2÷((7÷5)÷7))=10
(2÷((7÷7)÷5))=10
(2÷(7÷(5×7)))=10
(5×((2×7)÷7))=10
(5×((2+7)-7))=10
(5×(2×(7÷7)))=10
(5×(2+(7-7)))=10
(5×(2-(7-7)))=10
(5×(2÷(7÷7)))=10
(5×(7×(2÷7)))=10
(5×(7+(2-7)))=10
(5×(7-(7-2)))=10
(5×(7÷(7÷2)))=10
(5÷((7÷2)÷7))=10
(5÷((7÷7)÷2))=10
(5÷(7÷(2×7)))=10
(7×((2×5)÷7))=10
(7×(2×(5÷7)))=10
(7×(2÷(7÷5)))=10
(7×(5×(2÷7)))=10
(7×(5÷(7÷2)))=10
(7+((2×5)-7))=10
(7-(7-(2×5)))=10
(7÷((7÷2)÷5))=10
(7÷((7÷5)÷2))=10
(7÷(7÷(2×5)))=10