（ただし１と２を合せて１２のような使い方は出来ません。）
44個の解法が見つかりました。
(((2×8)-5)-1)=10
(((5+8)-1)-2)=10
(((5+8)-2)-1)=10
((1+5)+(8÷2))=10
((2×8)-(1+5))=10
((5+(8-1))-2)=10
((5+(8-2))-1)=10
((5+8)-(1+2))=10
((5-(1-8))-2)=10
((5-(2-8))-1)=10
((5-1)+(8-2))=10
((5-1)-(2-8))=10
((5-2)+(8-1))=10
((5-2)-(1-8))=10
((8+(5-1))-2)=10
((8+(5-2))-1)=10
((8-(1-5))-2)=10
((8-(2-5))-1)=10
((8-1)+(5-2))=10
((8-1)-(2-5))=10
((8-2)+(5-1))=10
((8-2)-(1-5))=10
((8÷2)+(1+5))=10
(1+(5+(8÷2)))=10
(5+((8-1)-2))=10
(5+((8-2)-1))=10
(5+(1+(8÷2)))=10
(5+(8-(1+2)))=10
(5-((1+2)-8))=10
(5-(1+(2-8)))=10
(5-(1-(8-2)))=10
(5-(2+(1-8)))=10
(5-(2-(8-1)))=10
(8+((5-1)-2))=10
(8+((5-1)÷2))=10
(8+((5-2)-1))=10
(8+(5-(1+2)))=10
(8-((1+2)-5))=10
(8-((1-5)÷2))=10
(8-(1+(2-5)))=10
(8-(1-(5-2)))=10
(8-(2+(1-5)))=10
(8-(2-(5-1)))=10