Răspuns:
5. a) ( 1/5 ) + ( - 1/5 ) = - 2/5
b) - 7/3 - ( + 5/3 ) = - 2/3
c) 11/4 - ( - 1/4 ) = + 12/4
d) + 1/3 - ( + 4/3 ) = - 2/4
e) - 2/5 - ( - 7/5 ) = + 5/5 = 1
f) 4/3 + ( - 1/3 ) = 3/3 = 1
