Expand $\frac{3.5}{5}$ by multiplying both numerator and the denominator by $10$.
$$1.75-\frac{35}{50}$$
Reduce the fraction $\frac{35}{50}$ to lowest terms by extracting and canceling out $5$.
$$1.75-\frac{7}{10}$$
Convert decimal number $1.75$ to fraction $\frac{175}{100}$. Reduce the fraction $\frac{175}{100}$ to lowest terms by extracting and canceling out $25$.
$$\frac{7}{4}-\frac{7}{10}$$
Least common multiple of $4$ and $10$ is $20$. Convert $\frac{7}{4}$ and $\frac{7}{10}$ to fractions with denominator $20$.
$$\frac{35}{20}-\frac{14}{20}$$
Since $\frac{35}{20}$ and $\frac{14}{20}$ have the same denominator, subtract them by subtracting their numerators.
