13+27\dfrac{1}{3} + \dfrac{2}{7}
13+27\dfrac{1}{3} + \dfrac{2}{7}
Since these fractions have different denominators, we need to find the least common multiple of the denominators
The least common multiple of 3 and 7 is 21, so we need to multiply to make each of the denominators = 21
13∗77=721\dfrac{1}{3} * \dfrac{7}{7} = \dfrac{7}{21}
27∗33=621\dfrac{2}{7} * \dfrac{3}{3} = \dfrac{6}{21}
Since these fractions have the same denominator, we can just add the numerators
721+621=1321\dfrac{7}{21} + \dfrac{6}{21} = \dfrac{13}{21}