K/1 (Kindergarten/1st grade): These students are at a stage where they are learning fundamental skills like reading, writing, and socializing. Mixing kindergarteners with first graders allows for natural peer teaching. First graders can model more advanced skills, helping kindergarteners develop confidence, while still being young enough to relate to their classmates.

2/3 and 4/5 Groupings: As students get older, they begin to develop more advanced thinking skills, and this kind of group helps cater to their growing independence. Students in 2nd and 3rd grades, or 4th and 5th grades, tend to share similar cognitive, social, and emotional development, allowing for tailored instruction and peer interactions that can advance both academic and social growth.

In mixed-age classrooms, older students can mentor younger students, which is highly beneficial for both groups:

• Older students get opportunities to reinforce their knowledge by teaching younger ones, enhancing their own understanding and building leadership skills.
• Younger students benefit from seeing more advanced peers as role models. It can boost their learning and motivation to develop skills by observing older students. The socialization with peers in the same age range also helps them grow emotionally and socially.

Teachers tailor lessons to the diverse developmental needs of the students within each group.

• Instead of focusing on a narrow range of abilities that would typically be expected in a single-grade class, teachers in multi-grade groupings can differentiate instruction to meet the needs of individual learners.
• Students who are struggling can get more individualized attention, while students who are excelling can be challenged more through enrichment activities.

• Grouping younger students (e.g., kindergarteners and first graders) with slightly older peers helps to alleviate the pressure that some young learners feel when they are placed in classrooms with a wide spread of abilities. Having a blend of ages within the class can create a more relaxed environment for learning.
• It also reduces the anxiety that some students experience when transitioning to a new grade level, as they already know older students in their classroom.

• When students from different grades are grouped together, they have the opportunity to develop stronger social bonds. Younger students can learn from older ones, and older students gain empathy and patience by working with younger peers.
• This helps create a positive, community atmosphere where students develop a sense of belonging and confidence.

• This structure allows for greater flexibility in grouping students based on abilities and needs. For instance, if a group of 1st graders excels in reading, they can work with 2nd graders in that area. Similarly, a group of 4th graders who need support in math could benefit from working with 5th graders who have mastered the content.
• Flexible grouping encourages collaboration and helps students progress at their own pace without being limited by grade-level constraints.

• Teachers of mixed-grade groups have the opportunity to work with students over two years (e.g., for both kindergarten and first grade in a K/1 grouping), allowing teachers to build stronger relationships with students and to get to know their learning needs better, fostering more personalized instruction. In some schools, the same teacher might work with the same group of students for multiple years (e.g., K/1 and then 2/3), which provides continuity. This kind of multi-year commitment is sometimes referred to as “looping.” A teacher follows the students from K/1 through 4/5 and then loops or cycles back to a new cohort at K/1. 
• It also helps students form long-term bonds with their peers, which can lead to greater social stability as they progress through school, and can also reduce student anxiety at the beginning of each new school year, when they may retain their teacher for at least two years in a row.