2. What is the sum of all of the prime numbers that are greater than 10 and less than 20? (A prime number is a positive integer greater than 1 whose only positive divisors are 1 and itself. For example. 7 is a prime number.)
2. The prime numbers that are greater than 10 and less than 20 are $11,13,17,19$.
(Since $12=2 \times 6$ and $14=2 \times 7$ and $15=3 \times 5$ and $16=2 \times 8$ and $18=2 \times 9$, none of these integers is a prime number.)
The sum of these prime numbers is
$$
11+13+17+19=(11+19)+(13+17)=30+30=60
$$

ANSWER: 60