In a week, Madeline spends 18 hours in class + 4 hours per day x 7 days = 18 + 28 = 46 hours on homework.
She also spends 8 hours per day x 7 days = 56 hours sleeping.
She works part-time for 20 hours per week.
So, in total, she spends 46 + 56 + 20 = 122 hours on these activities.
There are 7 days in a week, and each day has 24 hours, so in a week, there are 7 x 24 = 168 hours.
Therefore, Madeline has 168 - 122 = 46 hours left over.
#### 46
The answer is: 46
Below is a math problem. Provide a detailed, step-by-step solution.

### Problem:
Madeline spends 18 hours a week in class. She spends 4 hours per day working on homework. She spends 8 hours per day sleeping. She works part-time 20 hours per week. How many hours left over does Madeline have?

### Answer:
