Question: Ella collected $39$ shells at the beach. Her brother collected $28$ shells. How many shells did they collect in all?
1. **State the problem:** Ella collected $39$ shells and her brother collected $28$ shells. We need to find the total number of shells they collected together.
2. **Formula used:** To find the total, we add the number of shells collected by Ella and her brother.
$$\text{Total shells} = \text{Ella's shells} + \text{Brother's shells}$$
3. **Substitute the values:**
$$\text{Total shells} = 39 + 28$$
4. **Calculate the sum:**
$$39 + 28 = 67$$
5. **Answer:** They collected $67$ shells in all.