The problem asks how much Terry spent on socks after visiting a store 7 times, with each visit involving the purchase of 2 packages of socks costing $9 each.

We can calculate this step by step:

• Each visit, Terry buys 2 packages of socks at $9 each. Therefore, in each visit, he spends: $2 \times 9 = 18 \, \text{dollars per visit}$
• Since Terry visited the store 7 times, the total amount he spent is: $7 \times 18 = 126 \, \text{dollars}$ Thus, the correct expression representing this situation is: $7 \times (9 + 9)$ since $9 + 9$ represents the total cost for two packages per visit, and he visited 7 times.

This corresponds to option C: $7(9 + 9)$.

Would you like further details on the calculations or have any questions?

Here are five related questions to deepen your understanding:

1. How would the expression change if each package of socks cost $10?
2. If Terry bought 3 packages per visit, how would you modify the expression?
3. How can you represent the total amount using an addition-based expression rather than multiplication?
4. If Terry had only visited the store 5 times, how would you adjust the expression?
5. What would the expression be if Terry received a 10% discount on each package?

Tip: Always break down word problems step by step, identifying how many units of an item are bought and the cost per unit.