Question

At the begining of the month, Evan had $24 in his account at the school bookstore. Use a variable to represent the unknow quantity on a number line. What is the unkown quantity in each case?

First he bought some notebooks and pens that cost $16.
Then he deposited some more money and his account balance was $28.
Then he brought a book for English class that costs $34.
Then he deposited exactly enough money so that he paid off his debt to the bookstore.
Explain why it makes sense to use a negative number to represent Ecan's account balance when he owes money.
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Answer 1

he bought notebooks and pens for 16$

Explanation:

the untold infromation that leaves him with 8$

Answer 2

24-16 = 8
8 + 20 = 28
28-34 = -6
-6 + 6 = 0


he has nothing left