12. Efectuați:
a) (19/3 - 11/2) : 1/3; b) 15/14 × (5/3 - 4/15);
c) (13/3 - 17/4) : 1/6; d) 2/13 × (14/9 + 7/2);
e) (23/10 + 7/4) : 27/2; f) (11/6 - 3/8) × 12/7


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