（ただし１と２を合せて１２のような使い方は出来ません。）
43個の解法が見つかりました。
((4+5)+(8-7))=10
((4+5)-(7-8))=10
((4+8)+(5-7))=10
((4+8)-(7-5))=10
((4-7)+(5+8))=10
((5+(4+8))-7)=10
((5+7)-(8÷4))=10
((5+8)+(4-7))=10
((5+8)-(7-4))=10
((5-7)+(4+8))=10
((8+(4+5))-7)=10
((8-7)+(4+5))=10
(4+((5+8)-7))=10
(4+(5+(8-7)))=10
(4+(5-(7-8)))=10
(4+(8+(5-7)))=10
(4+(8-(7-5)))=10
(4-((7-5)-8))=10
(4-((7-8)-5))=10
(4-(7-(5+8)))=10
(5+((4+8)-7))=10
(5+(4+(8-7)))=10
(5+(4-(7-8)))=10
(5+(7-(8÷4)))=10
(5+(8+(4-7)))=10
(5+(8-(7-4)))=10
(5-((7-4)-8))=10
(5-((7-8)-4))=10
(5-((8÷4)-7))=10
(5-(7-(4+8)))=10
(7+(5-(8÷4)))=10
(7-((8÷4)-5))=10
(8+((4+5)-7))=10
(8+(4+(5-7)))=10
(8+(4-(7-5)))=10
(8+(4÷(7-5)))=10
(8+(5+(4-7)))=10
(8+(5-(7-4)))=10
(8-((7-4)-5))=10
(8-((7-5)-4))=10
(8-(4÷(5-7)))=10
(8-(7-(4+5)))=10