Pick two or fewer different digits from the set $\{1, 3, 6, 7\}$ and arrange them to form a number.  How many prime numbers can we create in this manner?
Question:
Pick two or fewer different digits from the set $\{1, 3, 6, 7\}$ and arrange them to form a number.  How many prime numbers can we create in this manner?
Answer:
Let's think step by step.

user
10
Pick two or fewer different digits from the set $\{1, 3, 6, 7\}$ and arrange them to form a number.  How many prime numbers can we create in this manner?
train