Find the sum of all prime numbers less than 20.

Options

A. 92
B. 73
C. 19
D. 77

Answer

To find the sum of all prime numbers less than 20, we can follow these steps:

### Step 1: Identify the prime numbers less than 20
Prime numbers are numbers greater than 1 that have no divisors other than 1 and themselves. The prime numbers less than 20 are:
- 2
- 3
- 5
- 7
- 11
- 13
- 17
- 19

### Step 2: List the identified prime numbers
We can list the prime numbers we found:
- 2
- 3
- 5
- 7
- 11
- 13
- 17
- 19

### Step 3: Add the prime numbers together
Now we will add these prime numbers:
- Start with the first two:
\( 2 + 3 = 5 \)
- Add the next prime number:
\( 5 + 5 = 10 \)
- Add the next:
\( 10 + 7 = 17 \)
- Continue adding:
\( 17 + 11 = 28 \)
- Next:
\( 28 + 13 = 41 \)
- Then:
\( 41 + 17 = 58 \)
- Finally:
\( 58 + 19 = 77 \)

### Step 4: State the final sum
The sum of all prime numbers less than 20 is \( 77 \).

### Final Answer
The sum of all prime numbers less than 20 is **77**.

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