Răspuns :
( 12 + 8 - 5 ) : 5 - ( 6 + 4 - 9 + 1 ) = .
= ( 20 - 5 ) : 5 - ( 10 - 9 + 1 ) .
= 15 : 5 - ( 1 + 1 ) .
= 15 : 5 - 2 .
= 3 - 2 .
= 1 .
(20-5):5-(10-8)=15:5-2=3-2=1
