Determine the number of fractions in the pattern below that are expressed in lowest terms.
1/2019, 2/2019, 3/2019, ..., 2019/2019
All numerators that are multiples of 3, from 3 to 2019 will express the fraction in lowest form:
[2019 - 3] / 3 + 1 ==673 fractions
Numerators that are multiples of three are able to express the fraction in lowest form, but aren't actually so expressed here. For example, 3/2019 isn't in lowest form.
And what about numerators that are multiples of 673?