What is the next number in the number sequence ?1,2,3,5,8,13,21,34,55,89,`……..`

Options

A. 90
B. 103
C. 127
D. 144

Answer

To find the next number in the sequence 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, we need to identify the pattern in the sequence.

### Step-by-Step Solution:

1. **Identify the Sequence**: The given sequence is 1, 2, 3, 5, 8, 13, 21, 34, 55, 89.

2. **Look for a Pattern**:
- The first number is 1.
- The second number is 2.
- The third number is 3, which is the sum of the first (1) and second (2) numbers:
\[ 1 + 2 = 3 \]

3. **Continue the Pattern**:
- The fourth number is 5, which is the sum of the second (2) and third (3) numbers:
\[ 2 + 3 = 5 \]
- The fifth number is 8, which is the sum of the third (3) and fourth (5) numbers:
\[ 3 + 5 = 8 \]
- The sixth number is 13, which is the sum of the fourth (5) and fifth (8) numbers:
\[ 5 + 8 = 13 \]
- The seventh number is 21, which is the sum of the fifth (8) and sixth (13) numbers:
\[ 8 + 13 = 21 \]
- The eighth number is 34, which is the sum of the sixth (13) and seventh (21) numbers:
\[ 13 + 21 = 34 \]
- The ninth number is 55, which is the sum of the seventh (21) and eighth (34) numbers:
\[ 21 + 34 = 55 \]
- The tenth number is 89, which is the sum of the eighth (34) and ninth (55) numbers:
\[ 34 + 55 = 89 \]

4. **Calculate the Next Number**:
- To find the next number after 89, we sum the ninth (55) and tenth (89) numbers:
\[ 55 + 89 = 144 \]

5. **Conclusion**: The next number in the sequence is 144.

### Final Answer:
The next number in the sequence is **144**.