\(\dfrac{11}{15}\) - \(\dfrac{13}{25}\) - \(\dfrac{1}{75}\) + \(\dfrac{4}{5}\)
= \(\dfrac{11\times5}{15\times5}\) - \(\dfrac{13\times3}{25\times3}\) - \(\dfrac{1}{75}\) + \(\dfrac{4\times15}{5\times15}\)
= \(\dfrac{55}{75}-\dfrac{39}{75}\) - \(\dfrac{1}{75}\) + \(\dfrac{60}{75}\)
= \(\dfrac{75}{75}\)
= 1