а) 513:
$$513 = 16 \cdot 32 + 1$$
$$32 = 16 \cdot 2 + 0$$
$$513 = 201_{16}$$
б) 600:
$$600 = 16 \cdot 37 + 8$$
$$37 = 16 \cdot 2 + 5$$
$$600 = 258_{16}$$
в) 2020:
$$2020 = 16 \cdot 126 + 4$$
$$126 = 16 \cdot 7 + 14$$
$$2020 = 7E4_{16}$$
Ответ:
а) $$201_{16}$$
б) $$258_{16}$$
в) $$7E4_{16}$$