15+18\dfrac{1}{5} + \dfrac{1}{8}
15+18\dfrac{1}{5} + \dfrac{1}{8}
Since these fractions have different denominators, we need to find the least common multiple of the denominators
The least common multiple of 5 and 8 is 40, so we need to multiply to make each of the denominators = 40
15∗88=840\dfrac{1}{5} * \dfrac{8}{8} = \dfrac{8}{40}
18∗55=540\dfrac{1}{8} * \dfrac{5}{5} = \dfrac{5}{40}
Since these fractions have the same denominator, we can just add the numerators
840+540=1340\dfrac{8}{40} + \dfrac{5}{40} = \dfrac{13}{40}