D.C. school staffer Jeremy Lykken prepares materials while sitting in the hallway of Kelly Miller Middle School on Aug. 4. Eleven city public schools will start their year-round academic years on Monday. (Christian K. Lee/The Washington Post)

It was the first week in August, and teachers at Kelly Miller Middle School were already scrambling to decorate classrooms and hone lesson plans.

The school’s more than 500 students will arrive Monday at the Washington Northeast campus for the first day of school as summer continues for most others in the Washington area. They will be in class weeks earlier than in years past.

Kelly Miller is one of 10 D.C. public schools that will embark on a new, year-round academic calendar starting Monday. Their academic year will have 20 more days than other schools in the system, with shorter and more frequent breaks during a school year that runs 200 days through all 12 months. One additional elementary school began the extended schedule during the 2015-2016 school year.

More than half of the city’s charter schools already embrace the schedule, which is the latest push to close the achievement gap in some of the District’s struggling schools. All but one of the 10 participating elementary and middle schools are in Wards 7 and 8, areas east of the Anacostia River that are among the city’s poorest and most underserved.

Teachers take part in an ice-breaker exercise at Kelly Miller Middle School on Aug. 4. (Christian K. Lee/The Washington Post)

Students who attend a year-round school will get the equivalent of nearly an extra year of instructional days by the time they start high school. Catrina Brown, a sixth-grade English teacher at Kelly Miller, said she believes it will help students.

“We’re looking at it as an adventure for the staff,” Brown said. “It’s a new experience, but we are excited because it gives kids more time to engage with the content. It allows teachers to go deeper into the content.”

In an attempt to combat the “summer brain drain,” the new schedule will mean that students and teachers will not have a long summer break, with the goal of retaining as much classroom learning as possible. The 2016-2017 academic year is scheduled to end July 17, 2017, and the following academic year is scheduled to start July 31, 2017.

Teachers at schools with the new schedule will switch from 10-month contracts to 12-month contracts, affecting 432 teachers at the 11 extended-year schools. Staff members who did not want to move to a year-round schedule had the option of teaching at other schools. Kelly Miller’s principal, Kortni Stafford, said 90 percent of the middle school’s staff decided to stay on, with three teachers and aides opting out.

“While I like my summer, I usually spend my summers doing education work anyway, teaching science classes at summer camp and the library,” said Rabiah Harris, a Kelly Miller science teacher.

The extended year will allow for more academic instruction and electives. Harris, for example, will be leading a new designing and modeling course that will teach students real-world applications of science topics. The students also will meet multiple times a week for advisory sessions, during which the youths will break into small groups by gender, sit in a circle and discuss social issues, current events, bullying and anything else they want to share under a teacher’s guidance.

“We haven't had space for this before,” Stafford said. “This is just building in time for them to know themselves and their classmates and build a relationship with an adult in the building.”

Struggling students will receive extra help in their core subjects during regularly scheduled sessions in the week. Stafford said students previously had to leave their classes for extra instruction. All schools participating in the year-round schedules will have “intersession” programming offering additional help at school during their seasonal breaks.

The overarching goal is to give students at the struggling schools a better chance at finding academic success and making it to high school graduation. During the 2014-2015 school year at Kelly Miller, about 70 percent of students did not meet, or partially met, expectations on the English and math portions of the standardized tests linked to Common Core.

“These are schools where not all the kids are reaching their potential,” Jennifer C. Niles, deputy mayor for education, said when the extended school years were announced in February.

Raymond Elementary in Petworth was the system’s pilot school for the new schedule and just completed its first year-round academic calendar. School officials hailed it as a success, although they said it is too early to provide concrete data showing results. Janae Hinson, a school system spokeswoman, said 96 percent of Raymond students opted to attend the intersession days during breaks for extra academic coaching.

Melinda Noble, a fourth-grade special education teacher at Raymond, said the normal summer break often caused a fair amount of learning loss but after shorter breaks “their minds came back refreshed.”

“It’s a good thing, because it gives additional time for students to achieve more,” Noble said.

The year-round schools are:

●H.D. Cooke Elementary in Adams Morgan.

●Garfield, Hendley, King, Randle Highlands, Thomas and Turner elementary schools and Hart, Johnson and Kelly Miller middle schools in Wards 7 and 8.