“There was very little mathematical discourse throughout the building,” Grange says. “There was a lot of talk about reading. We’d been through a thousand reading programs.”

Grange had taught fifth and sixth grade for about 30 years when he became Halecreek’s math interventionist in 2023–24, the same year the school piloted Happy Numbers. First-grade teacher Tiffany Markavich happened to hear about the program (by email, Grange thinks) and told him and principal Christopher Parker. The school’s other programs were not really schoolwide, so Grange suggested piloting this one.

The school asked teachers to use it 45 minutes a week that first year, as a way to “dip a toe.” By about halfway through that year, Grange had come to see Happy Numbers as the building’s primary data source alongside NWEA. From 2024–25, the school asked for an hour a week.

Grange began with an enrichment group and an intervention group, pulling about three students from each class. His intervention groups have grown to as many as 10 or 12 students, he says, because he can pinpoint the skill each student is working on and work out how to get them to the next level and out of the group.

When a student is ready to leave a group, Grange moves them out. His main tool for those moves is the yearly progress report. “I like seeing that green needle go across,” he says, “to see if we can take kids who were below grade level and get them to a position where they’re above grade level.”

A number of students have moved from intervention up to enrichment within six months to a year, after intensive instruction in the group with Happy Numbers driving it.

In his groups, Grange watches each student’s work in the program and can take two or three minutes, he says, to give a quick lesson that keeps the student in their zone of proximal development. Then the student goes right back to applying it.

Seeing how well that worked in his intervention groups, a few teachers, Markavich among them, began using the program to help drive their own instruction, Grange says. In 2025–26, she grouped her first-grade class by the skill each student was working on. She taught her daily lesson to one group while another practiced that skill in Happy Numbers, then switched. “I think that’s kind of going to change the way she teaches her math from this point forward,” he says.

An example of the skills report. Each skill has a color for each student (mastered, developing, or help needed), and an icon marks the skill they’re working on now.

For the first two years, Grange visited every class on Fridays with the weekly progress report to give each student kudos or a pick-me-up. When a student came to him saying they had done 22 tasks that week, he would answer, “Yeah, but you’re only at 57 percent accuracy. That has to change.”

“Hey, Mr. Grange, did you see the accuracy that I have this week?” other students would ask him. By 2025–26, he found the Friday visits less necessary, because students knew what was expected of them and “just kind of got after it.”

In the lunchroom, the hallway, or the library, he can pull a student aside to talk about common denominators or converting mixed numbers to improper fractions, and the student is the one using the math vocabulary. “That just did not happen before,” he says.

Grange reads each student’s Happy Numbers progress beside their NWEA results to see which skills they still need for the next grade level.

Before the pilot, the share of students reaching their spring NWEA growth goal in math had been consistently around 45 to 50 percent. With teachers using Happy Numbers about an hour a week, he puts it at 84 or 85 percent in 2024–25 and very close to that in 2025–26. He says much of what he describes comes from both his new role and the pilot.

Happy Numbers’ own data agrees. In 2025–26, students who used the program regularly gained well over a full grade level on average.