Sum of the first 20 natural numbers will be :

Options

A. 120
B. 210
C. 240
D. `245`

Answer

To find the sum of the first 20 natural numbers, we can use the formula for the sum of the first N natural numbers, which is given by:

\[ S = \frac{N(N + 1)}{2} \]

### Step-by-Step Solution:

**Step 1: Identify N**
- Here, we need to find the sum of the first 20 natural numbers, so \( N = 20 \).

**Step 2: Substitute N into the formula**
- Substitute \( N = 20 \) into the formula:
\[ S = \frac{20(20 + 1)}{2} \]

**Step 3: Calculate \( N + 1 \)**
- Calculate \( 20 + 1 \):
\[ 20 + 1 = 21 \]

**Step 4: Multiply N and \( N + 1 \)**
- Now multiply \( 20 \) and \( 21 \):
\[ 20 \times 21 = 420 \]

**Step 5: Divide by 2**
- Finally, divide the result by 2:
\[ S = \frac{420}{2} = 210 \]

### Final Answer:
The sum of the first 20 natural numbers is **210**.