Google Classroom
GeoGebraGeoGebra Classroom

7.3.1Adding Fractions

Finding the LCD

In order to add two fractions, we must first make sure we can find the LCD of the two fractions first. The LCD is the Least Common Denominator of the 2 fractions. We can find it by finding the least common multiple of the denominators. So we keep adding the denominators onto themselves until we find the least common one.

Exercise

Use the model below to visualize adding fractions using the least common denominator.

Instructions for Model

Move the sliders to manipulate the numerators and denominators of both fractions. We can go up to 10/10 on both sides. Match the given numbers, then slide one diagram onto the other to get the LCD.