$$30\%$$ of $$200$$ + $$20\%$$ of $$450 – 25\%$$ of $$600$$
$$= (\dfrac{30 }{ 100} \times 200) + (\dfrac{20 }{ 100} \times 450) – (\dfrac{25 }{ 100} \times 600)$$
$$= (30 \times 2) + (2 \times 45) – (25 \times 6)$$
We get,
$$= 60 + 90 – 150$$
$$= 150 – 150$$
$$= 0$$