tính nhanh:
a) \(\dfrac{1}{3}\) - \(\dfrac{3}{4}\) - ( - \(\dfrac{3}{5}\)) + \(\dfrac{1}{4}\) - \(\dfrac{2}{9}\) - \(\dfrac{1}{36}\) + \(\dfrac{1}{15}\)
b) \((3-\dfrac{1}{4}+\dfrac{2}{3})\) - \((5+\dfrac{1}{3}-\dfrac{6}{5})\) - \((6-\dfrac{7}{4}+\dfrac{3}{2})\)
c) 442 x 195 - 2 x 95 x 221