Julia bought 534 pounds of potatoes at the farmers market. Leeyana bought 15 pounds of...

Step 1
The addition(subtraction) between two like fractions can be done by adding(subtracting) the numerators of both fractions by fixing same denominator to the result. Like fractions are the fraction with the same denominator.
For the addition (subtraction) between two unlike fractions, first we have to convert both denominators of the fractions to the same value. This can be done by finding the LCM(Least Common multiple) of the denominators of the fractions. We can multiply and divide both the fractions by suitable constant to produce the same value in both denominators.
The mixed fraction can be converted to an improper fraction as,
${\displaystyle \text{whole}\frac{\nu mera\to r}{denomina\to r}=\frac{(\text{whole}\times \text{denominator})+\text{numerator}}{\text{denominator}}}$
Step 2
The number of pounds of potatoes bought by Julia is ${\displaystyle 5\frac{3}{4}}$
The number of pounds of potatoes bought by Leeyana is ${\displaystyle \frac{1}{5}}$
The number of pounds of potatoes bought by Gabriela is ${\displaystyle 1\frac{1}{2}}$
The total number of pounds of potatoes bought by Julia, Leeyana, and Gabriela is (1) ${\displaystyle 5\frac{3}{4}+\frac{1}{5}+1\frac{1}{2}}$
Now convert the mixed fractions to an improper fractions,
${\displaystyle 5\frac{3}{4}=\frac{(5\times 4)+3}{4}}$
${\displaystyle =\frac{20+3}{4}}$
${\displaystyle =\frac{23}{4}}$
${\displaystyle 1\frac{1}{2}=\frac{(1\times 2)+1}{2}}$
${\displaystyle =\frac{2+1}{2}}$
${\displaystyle =\frac{3}{2}}$
Now we can simplify the addition expression (1),
${\displaystyle 5\frac{3}{4}+\frac{1}{5}+1\frac{1}{2}=\frac{23}{4}+\frac{1}{5}+\frac{3}{2}}$
${\displaystyle =(\frac{23}{4}+\frac{3}{2})+\frac{1}{5}}$
${\displaystyle =(\frac{23}{4}+\frac{3}{2}\times \frac{2}{2})+\frac{1}{5}}$
${\displaystyle =\frac{23}{4}+\frac{6}{4}+\frac{1}{5}}$
${\displaystyle =\frac{29}{4}+\frac{1}{5}}$
${\displaystyle =\frac{29}{4}\times \frac{5}{5}+\frac{1}{5}\times \frac{4}{4}}$
${\displaystyle \{theLCMof(4,2)=4,(4,5)=20\text{convert to the denominators}\}}$
${\displaystyle =\frac{149}{20}}$
${\displaystyle =7\frac{9}{20}}$
Hence the total number of pounds of potatoes bought by Julie, Leeyana, and Gabriela is ${\displaystyle 7\frac{9}{20}}$ pounds.