If x is any real number, then $${{{x^2}} \over {1 + {x^4}}}$$ belongs to which one of the following intervals?

If $$f(x) = {x \over 2} - 1$$, then on the interval [0, $$\pi$$] which one of the following is correct?

Which one of the following graph represents the function $$f(x) = {x \over x},x \ne 0$$ ?

Let $$f(n) = \left[ {{1 \over 4} + {n \over {1000}}} \right]$$, where [x] denote the integral part of x. Then the value of $$\sum\limits_{n = 1}^{1000} {f(n)} $$ is