Number and Operations—Fractions: Adding and Subtracting Fractions with Unlike Denominators (CCSS.5.NF.1)

Use fraction bars split into eighths. Rewrite $\frac{1}{4}$ as $\frac{2}{8}$ so the bars match. Then add: $\frac{3}{8} + \frac{2}{8} = \frac{5}{8}$. On the fraction bar model, you would see 5 of the 8 equal parts shaded.

Use fraction bars with twelfths. Rewrite $4\tfrac{2}{3}$ as $4\tfrac{8}{12}$ and $3\tfrac{1}{2}$ as $3\tfrac{6}{12}$. Subtract whole parts and fractional parts: $(4-3)+(\tfrac{8}{12}-\tfrac{6}{12})=1+\tfrac{2}{12}=1\tfrac{1}{6}$ after simplifying $\tfrac{2}{12}$ to $\tfrac{1}{6}$. A bar model split into 12 parts shows the $\tfrac{8}{12}$ bar is two parts longer than the $\tfrac{6}{12}$ bar.

Make equivalent fractions with a common denominator. Using twentieths: $\frac{7}{10} = \frac{14}{20}$ and $\frac{1}{4} = \frac{5}{20}$. Subtract: $\frac{14}{20} - \frac{5}{20} = \frac{9}{20}$. A fraction-bar model split into 20 equal parts shows 14 shaded; removing 5 leaves 9 shaded.