Question

How many positive integers not exceeding 1000 are not divisible by either 4 or 6?

Answer 1

$\left\lfloor\dfrac{1000}4\right\rfloor=250$

$\left\lfloor\dfrac{1000}6\right\rfloor=166$

$\left\lfloor\dfrac{1000}{\mathrm{lcm}(4,6)}\right\rfloor=\left\lfloor\dfrac{1000}{12}\right\rfloor=83$

$250+166-83=333$