1. **Stating the problem:** Andreas caught four fish weighing a total of 1.5 kilograms. Three fish weigh 2.6 hg, 425 g, and 0.3 kg respectively. We need to find the weight of the fourth fish in grams. 2. **Convert all weights to the same unit (grams):** - 1.5 kg = 1500 g - 2.6 hg = 2.6 \times 100 = 260 g - 425 g = 425 g - 0.3 kg = 0.3 \times 1000 = 300 g 3. **Sum the weights of the three known fish:** $$260 + 425 + 300 = 985 \text{ g}$$ 4. **Calculate the weight of the fourth fish:** $$\text{Weight of fourth fish} = 1500 - 985 = 515 \text{ g}$$ 5. **Answer:** The fourth fish weighs **515 grams**.