How much heat turns 0.40 kg of ice at -15 °C into water at 35 °C? …

Step 1. Warm the ice. $0.40\ \text{kg} \times 2100\ \text{J kg}^{-1}\text{K}^{-1} \times 15\ \text{K} = 12\,600\ \text{J}$.

Step 2. Melt it. $0.40\ \text{kg} \times 3.34 \times 10^{5}\ \text{J/kg} = 133\,600\ \text{J}$.

Step 3. Warm the water. $0.40\ \text{kg} \times 4186\ \text{J kg}^{-1}\text{K}^{-1} \times 35\ \text{K} = 58\,604\ \text{J}$.