Denver’s University Prep faced a gargantuan task last year: Turn around a school where the previous year just 7 percent of third- through fifth-graders were on grade level in math and 6 percent were on grade level in English.

On Friday morning, dozens of those students — dressed in khaki pants and button-up sweaters — clustered on the lawn to listen to officials celebrate their charter school, University Prep Steele Street, for showing the most academic growth in Colorado on last spring’s state standardized math tests.

The high-poverty school also had the eighth-highest growth on state English tests. Another Denver charter, KIPP Northeast Denver Leadership Academy high school, had the first-highest.

“I want to say clearly to all of you that no one is ever going to tell you what you can and can’t do — ever,” University Prep founder and executive director David Singer told his students. “You’re going to remind them what you did in a single year.”

By the end of last year, 43 percent of University Prep Steele Street third- through fifth-graders were at grade level in math and 37 percent were at grade level in English, according to state tests results released Thursday.

University Prep Steele Street students scored better, on average, than 91 percent of Colorado students who had similar test scores the year before in math and better than 84 percent of students who had similar scores in English.

As Singer noted Friday, that type of skyrocketing improvement is rare among turnaround schools in Denver and nationwide.

“This might be one of the biggest wins we’ve ever seen in our city, our state, and our country of what it truly means to transform a school,” he said.

Many of the kids were previously students at Pioneer Charter School, one of the city’s first-ever charters. Founded in 1997 in northeast Denver, Pioneer had struggled academically in recent years, posting some of the lowest test scores in all of Denver Public Schools.

In 2015, Pioneer’s board of directors decided to close the school, which served students in preschool through eighth grade. University Prep, an elementary charter school a couple miles away, applied to take it over. But unlike many school turnarounds, it wouldn’t be a gradual, one-grade-at-a-time, phase-in, phase-out transition. Instead, University Prep would be responsible for teaching students in kindergarten through fifth grade on day one.

“When Pioneer Charter School became an option and we looked at our results up to that point of time and what we believed to be our capacity … we saw an opportunity,” Singer said.

A former math teacher at nearby Manual High School, which has itself been subject to several turnaround efforts, Singer started University Prep after becoming frustrated with the reality faced by many of his teenage students, who often showed up with gaps in their knowledge.

“When you walk into school at 14 or 15 and have a huge gap, the likelihood you get to be whatever you want to be is diminished,” he said.

The key to changing that, Singer realized, would be to start students on a path to success earlier. That’s why University Prep’s tagline is, “College starts in kindergarten.”

“It’s a significantly better pathway than the one of intense catch-up on the backend,” Singer said.

University Prep Arapahoe Street opened as a standalone charter school in 2010. Last year, its fourth- and fifth-graders outperformed district averages on both the English and math tests.

Several teachers and staff members from the original campus helped open Steele Street in 2016. The school started with 226 students, 89 percent of whom qualified for subsidized lunches. Ninety-seven percent were students of color and 71 percent were English language learners, more than twice the percentage in the district as a whole.

The biggest difference from the year before, Singer said, were the expectations. The work was more rigorous and there was more of it: three hours of literacy and more than 100 minutes of math each day as part of a schedule that stretched from 7:15 a.m. to 4 p.m.

Lauren Argue was one of the teachers that moved from the original campus to Steele Street. She and Singer said the other big difference was the honest feedback students received from their teachers. That included sharing with students the fact that they were several grade levels behind, and starting the year by re-teaching second-grade math to fourth-graders.

“We had conversations of, ‘Here is where you’re at,’ but also expressing our unwavering belief that, ‘By the end of the year, you will grow a tremendous amount,’” Argue said.

While those hard conversations may have been uncomfortable at first for students and their families, Argue said they embraced them once they saw the progress students were making — progress that teachers made sure to celebrate at every opportunity.

“Kids learned the joy of what it means to do hard academic work and get through to the other side,” Singer said. “That became a source of pride.”

Ten-year-old Abril Sierra attended Pioneer since preschool. This year, she’s a fifth-grader at University Prep. On Friday, she said that while at times she thought her brain might explode, it felt good to tackle harder work. She credited her teachers with helping her achieve.

“The things that changed were definitely the perspective of how the teachers see you and believe in you,” Sierra said. “…They make you feel at home. You can trust them.”