1. **State the problem:** The grocer buys 620 kg of onions, correct to the nearest 20 kg, and packs them into bags each containing 5 kg of onions, correct to the nearest 1 kg. We need to calculate the upper bound for the number of bags. 2. **Understanding bounds:** - Since the total weight is correct to the nearest 20 kg, the maximum possible weight (upper bound) is $$620 + 10 = 630$$ kg. - Since each bag's weight is correct to the nearest 1 kg, the minimum possible weight per bag (lower bound) is $$5 - 0.5 = 4.5$$ kg. 3. **Formula for upper bound of number of bags:** $$\text{Upper bound of number of bags} = \frac{\text{Upper bound of total weight}}{\text{Lower bound of weight per bag}}$$ 4. **Calculate upper bound:** $$\frac{630}{4.5} = 140$$ 5. **Interpretation:** The upper bound for the number of bags is 140. **Final answer:** $$\boxed{140}$$