What is the smallest number divisible by all of the integers 1 through 9?

The smallest number that is divisible by all integers from 1 to 9 is known as the least common multiple (LCM) of these numbers. To find this, we need to determine the highest powers of the prime factors for each number from 1 to 9.

The prime factorization of each number is as follows:

  • 1 = 1
  • 2 = 2
  • 3 = 3
  • 4 = 22
  • 5 = 5
  • 6 = 2 × 3
  • 7 = 7
  • 8 = 23
  • 9 = 32

The LCM will include each prime number raised to the highest power that appears in these factorizations:

  • For the prime number 2, the highest power is 23 (from 8).
  • For the prime number 3, the highest power is 32 (from 9).
  • For the prime number 5, the highest power is 51 (from 5).
  • For the prime number 7, the highest power is 71 (from 7).

Now we can calculate the LCM by multiplying these together:

LCM = 23 × 32 × 51 × 71 = 8 × 9 × 5 × 7

Calculating this step-by-step:

  • 8 × 9 = 72
  • 72 × 5 = 360
  • 360 × 7 = 2520

Therefore, the smallest number that is divisible by all integers from 1 through 9 is 2520.

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