If I spend $12 on lunch and $8 on coffee, how much have I spent in total?

To find the total amount spent, you need to add the cost of lunch to the cost of coffee. In this case, you spent $12 on lunch and $8 on coffee.

When you perform the addition:

[

12 + 8 = 20

]

This calculation shows that you have spent a total of $20. Therefore, the correct answer is the amount that accurately reflects this sum. Each step in the calculation is straightforward; you simply combine the two amounts to arrive at the total expenditure.