1357:
1 - 3 + 5 + 7
( 1 - 3 ) + 5 + 7
1 - 3 + ( 5 + 7 )
( 1 - 3 + 5 ) + 7
(( 1 - 3 ) + 5 ) + 7
( 1 - 3 ) + ( 5 + 7 )
1 - ( 3 - 5 ) + 7
( 1 - ( 3 - 5 )) + 7
1 - ( 3 - ( 5 + 7 ))
1 - ( 3 - 5 - 7 )
1 - (( 3 - 5 ) - 7 )
1 - 3 + 5 + 7
( 1 - 3 ) + 5 + 7
1 - 3 + ( 5 + 7 )
( 1 - 3 + 5 ) + 7
(( 1 - 3 ) + 5 ) + 7
( 1 - 3 ) + ( 5 + 7 )
1 - ( 3 - 5 ) + 7
( 1 - ( 3 - 5 )) + 7
1 - ( 3 - ( 5 + 7 ))
1 - ( 3 - 5 - 7 )
1 - (( 3 - 5 ) - 7 )