a; \(\dfrac{17}{76}\) < 1
\(\dfrac{84}{83}\) > 1
\(\dfrac{17}{76}\) < 1 < \(\dfrac{84}{83}\)
Vậy \(\dfrac{17}{76}\) < \(\dfrac{84}{83}\)
b; \(\dfrac{12}{47}\) > \(\dfrac{12}{48}\) = \(\dfrac{1}{4}\)
\(\dfrac{19}{77}\) < \(\dfrac{19}{76}\) = \(\dfrac{1}{4}\)
\(\dfrac{12}{47}\) > \(\dfrac{1}{4}\) > \(\dfrac{19}{77}\)
Vậy \(\dfrac{12}{47}\) > \(\dfrac{19}{77}\)