In order to out a fraction in lowest terms, you must divide by the Greatest Common Factor, or GCM, of the numerator and denominator in the fraction. Let's say we have the fraction 25/100. We know that the greastest common factor of 25 and 100 is 25, as 25 ÷ 25 = 1 and 100 ÷ 25 = 4 so 25/100 in lowest terms is 1/4:
25 25 1
___ ÷ ___ = ___
100 25 4
If the GCM of a fraction equals 1, the fraction is simplified. Because the only common factor of 1 and 4 is 1, we know this fraction is simplified.
1 1 1
__ ÷ ___ = ___
4 1 4
Hope this helps <3 Please contact me if your still confused