The question is ambiguous. It could mean:
- What is the smallest number divisible by both 1 and 9?
- What is the smallest number divisible by all integers from 1 to 9 (inclusive)?
We will answer both interpretations.
Interpretation 1: Smallest Number Divisible by 1 and 9
The smallest number divisible by both 1 and 9 is 9. Any number divisible by 9 is also divisible by 1.
Interpretation 2: Smallest Number Divisible by 1 Through 9
The smallest number divisible by all the integers from 1 to 9 is their Least Common Multiple (LCM). To find the LCM, we can use prime factorization.
- 1 = 1
- 2 = 2
- 3 = 3
- 4 = 2 x 2 = 22
- 5 = 5
- 6 = 2 x 3
- 7 = 7
- 8 = 2 x 2 x 2 = 23
- 9 = 3 x 3 = 32
To find the LCM, take the highest power of each prime number that appears in the factorizations:
- 23 = 8
- 32 = 9
- 5 = 5
- 7 = 7
Multiply these together: 8 x 9 x 5 x 7 = 2520.
Therefore, the smallest number divisible by all integers from 1 to 9 is 2520.