折线图显示了马可从周二到周五每天收到的短信数量。 在哪一天，马可收到的短信数量最接近他从周二到周五收到的短信平均数？ 答：___

1. Read the number of messages for each day from the graph

Tuesday: $56$
Wednesday: $32$
Thursday: $24$
Friday: $40$

2. Calculate the total number of messages received from Tuesday to Friday

$\text{Total} = 56 + 32 + 24 + 40 = 152$

3. Calculate the average number of messages

$\text{Average} = \frac{152}{4} = 38$

4. Determine which day's number of messages is closest to the average

Difference for Tuesday: $|56 - 38| = 18$
Difference for Wednesday: $|32 - 38| = 6$
Difference for Thursday: $|24 - 38| = 14$
Difference for Friday: $|40 - 38| = 2$

The smallest difference is $2$, which corresponds to Friday.