1. **State the problem:** We need to find the ratio of glass to cardboard in a recycling bin, where the glass weighs 2 kg and the cardboard weighs 500 g. 2. **Convert units to be consistent:** Since 1 kg = 1000 g, convert 2 kg of glass to grams: $$2\text{ kg} = 2 \times 1000 = 2000\text{ g}$$ 3. **Write the ratio:** The ratio of glass to cardboard is: $$\frac{2000\text{ g}}{500\text{ g}}$$ 4. **Simplify the ratio:** Divide numerator and denominator by 500: $$\frac{2000 \div 500}{500 \div 500} = \frac{4}{1}$$ 5. **Final answer:** The simplest form of the ratio of glass to cardboard is: $$4:1$$ This means there is 4 times as much glass as cardboard in the bin.