Consider the question. 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?
 If the answer is '46'; explain the reasoning:
Madeline spends 4 * 7 = 28 hours on homework. She spends 8 * 7 - 56 hours sleeping. Therefore, she is busy 28 + 18 + 56 + 20 = 122 hours per week. There are 7 * 24 = 168 hours per week. Thus, Madeline has 168 - 122 = 46 hours left over.