va rog repede!!!!!!!!

Răspuns:
a) 1) 9/30+4/20=18/60+12/60=³⁰30/60=1/3
2)1/3-7/14=14/42-21/42=⁷7/42=1/6
b) 1) 6/28+6/12=72/336+168/336=³240/336 = ⁴80/112 =⁴20/28=5/7
2) 5/7-10/35=25/35-10/35=⁵15/10=3/2