Find the least common denominator (LCM) of both fractions in order to determine if one fraction is equal to the other. In this case, the LCM will be 21, because both of the denominators, 3 and 7, are factors of 21.
To get the denominator of 1/3, which is 3, to turn into 21, we must multiply it by 7. Then multiply the numerator by 7 in the process, since that is one of the rules of fractions.
(1 * 7)/(3 * 7) = 7/21 This is the first fraction. Now do the same thing to the other fraction, except multiply by 3 in order to get a denominator of 21.
(2 * 3)/(7 * 3) = 6/21 This is the second fraction.
Comparing 7/21 and 6/21, if we were to just ignore the denominators, we can clearly see that 7 is not equal to 6, therefore, 1/3 is not equal to 2/7.