Why is teaching adding fractions with unequal denominators so hard?
Fractions have always been my students’ Achilles heel even before the math standards changed. I’m sure you know that many of the fraction concepts that were once taught in middle school have been moved to fourth and fifth grade.
Since I’ve taught middle school the new content for these grade levels didn’t scare me, but what did scare me was teaching more complex concepts to young learners.
I just couldn’t wrap my mind around teaching adding fractions with unequal denominators to nine and ten year old students!
When I taught middle school there were sixth and seventh graders who couldn’t master adding fractions and now I have to teach the same content to fifth graders. I wasn’t scared I was petrified! It showed in my test scores the first time I taught the new standards to my fifth graders.
Missing prerequisite skills
That summer I came up with a plan to scaffold the skills that were needed to actually master this concept.
Before I could scaffold the skills I had to identify what fraction skills were needed before they could actually attempt to add fractions with unequal denominators.
There were a few prerequisites skills that the students needed, but the most important skill that was to understand the unit fractions and decomposing fractions. I realized that these two skills laid the foundation for any work with fractions.
Identifying the prerequisite skills was an important step for me, because most of my students came to fifth grade working at a third or fourth grade level.
Understanding Fraction Models
It takes at minimum five steps to add fractions with unequal denominators.
The steps include but are not limited to:
- Create equivalent fractions
- Find the scale factor
- Add the fractions
- Convert to a mixed number (if necessary)
- Simplify ( if necessary)
With this many steps for one skill starting with the algorithm is NOT an option!
A lot of teachers don’t realize how important models are for fifth graders, because the curriculum makes the assumption that the students have a good fraction foundation.
Teaching adding fractions with unequal denominators can difficult, but if you identify the missing prerequisite skills and scaffold your lessons while using the appropriate fraction models teaching this skill should be less frustrating for you and students.