It’s back to school today for about one-third of Chicago Public Schools students, more than 115,000 kids.

Monday is the first day of Mayor Rahm Emanuel’s longer school day—seven hours for elementary students, seven-and-a-half-hours for high schoolers.

All grammar schools will now have recess. At some schools, this is the first time in decades kids will have a chance to jump rope or play tag during school.

Schools CEO Jean-Claude Brizard says the 243 schools opening Mondaywill be teaching to Illinois’ new “common core” standards.

“Parents should see curricular changes. In mathematics, much more conceptually based mathematics. Much more nonfiction in literacy.”

Chicago teachers return to the classroom without a contract. Brizard says the district is making “decent progress” in negotiations, and he’s optimistic the rest of the district’s schools will also open on time, after Labor Day.

The Chicago Teachers Union says it continues to bargain but is also preparing for a possible strike.