An educational software company is moving into an office in Charlestown’s City Square.

Six Red Marbles recently agreed to a five-year lease for 10,490 sq. ft. of office space located in the six-story building at 10 City Square. The company, which builds learning software for students in grades K-12, will occupy about 30 percent of the building, according to a press release from Avison Young real estate company.

Six Red Marbles works with schools, universities, foundations and technology companies and has done work for major publishing clients such as McGraw-Hill, Houghton Mifflin Harcourt and Pearson, according to the release.

The software company joins seven other businesses in the building, including Direct Invest LLC, Managed Technology Partners, Mollibrands, Thompson Engineering Company, Todd English Enterprises Olives Group, Town Hill Dry Cleaners and Wallwork, Curry, McKenna. The building is owned by City Square Holdings LLC.

Space is still available in the building—up to 5,470 sq. ft. on the fourth floor that can be subdivided, according to the release from Avison Young.