Question: Maria has $39$ apples. She gave to her friend, Besty $20$ apples while her another friend Viggie $10$ apples. How many apples have Maria left?
1. **State the problem:** Maria starts with $39$ apples. She gives $20$ apples to Besty and $10$ apples to Viggie. We need to find how many apples Maria has left.
2. **Formula used:** To find the remaining apples, subtract the total apples given away from the initial amount.
$$\text{Apples left} = \text{Initial apples} - (\text{Apples given to Besty} + \text{Apples given to Viggie})$$
3. **Calculate total apples given away:**
$$20 + 10 = 30$$
4. **Calculate apples left:**
$$39 - 30 = 9$$
5. **Answer:** Maria has $9$ apples left after giving apples to her friends.