Answer: 4
Explanation:
You can write an algebraic expression to represent the sequence with the books in this way:
- yesterday she got five books: 5
- today returned three books: - 3
- how many books did Gia have to begin: n
- At the end she has six books, which means that you can set an equality:
n + 5 - 3 = 6
Now you follow these steps to clear the unknown:
- do the operations in the left side: n + 2 = 6
- use subtraction property of equality: n = 6 - 2
- do the operations: n = 4
And that is the number of books whith which Gina started: 4
