Câu a) \(\dfrac{31995-81}{42660-108}=\dfrac{31914}{42552}=\dfrac{31914:10638}{42552:10638}\)
=\(\dfrac{3}{4}\)
Câu b) \(\dfrac{\left(3.5.7.11.13.15.37-10101\right)}{121212+40404}\)
=\(\dfrac{\left(3.5.7.11.13.15.37-3.7.13.37\right)}{3.7.13.37.12+3.7.13.37.4}\)
=\(\dfrac{3.7.13.37\left(5.11.15-1\right)}{3.7.13.37\left(12+4\right)}\)
= \(\dfrac{824}{16}\)=\(\dfrac{103}{2}\)
a) \(\dfrac{31995-81}{42660-108}=\dfrac{31914}{42552}=\dfrac{3}{4}\)
b: \(\dfrac{3\cdot5\cdot7\cdot11\cdot37-10101}{1212120+40404}=\dfrac{32634}{1252524}=\dfrac{21}{806}\)