Lesson 5: Use visual models to add two fractions with related units using the denominators 2, 3, 4, 5, 6, 8, 10, and 12.

Property

To add fractions with related denominators (where one denominator is a multiple of the other), use a tape diagram to decompose the fraction with the larger units.
Partition its parts into smaller, equivalent units to match the denominator of the other fraction, creating like units for addition.

Examples

Property

To add fractions on a number line, partition the line into the smaller unit (larger denominator) to create common units.
Model the first fraction with a jump from 0.
From that point, model the second fraction with another jump to find the sum.

Examples

Property

To add fractions with related denominators, such as $\frac{a}{b} + \frac{c}{d}$ where $d$ is a multiple of $b$, find a number $n$ so that $b \times n = d$.
Then, convert $\frac{a}{b}$ to an equivalent fraction and add:

Examples