100000:999

If this is a ratio:

• The greatest common divisor gcd(100000, 999) = 1, so the ratio is already in lowest terms: 100000:999.

If you want the decimal value of the division:

• 100000 / 999 = 100.100100100... (the repeating block is "100")

In repeating-decimal form: 100. \overline{100}.