1.tính nhanh nếu có thể
a)\(\frac{4}{11}\)-\(\frac{7}{15}\)+\(\frac{7}{11}\)-\(\frac{5}{15}\)
b)\(\frac{7}{3}\)-\(\frac{4}{9}\)-\(\frac{1}{3}\)-\(\frac{5}{9}\)
c)\((\frac{-1}{4}\)+\(\frac{7}{33}\)-\(\frac{5}{3}\)\()\)
d)\(\frac{-3}{4}\)\(\times\frac{8}{11}\)-\(\frac{3}{11}\)\(\times\frac{1}{2}\)
e)\(\frac{1}{15}\)+\(\frac{1}{35}+\frac{1}{63}+\frac{1}{99}+\frac{1}{143}+\frac{1}{195}\)