Katherine Hoffmore, 48, occupies her students in line at Greer Elementary as they get ready to go home for the day. Expected to cost about $7.5 million a year for salaries and benefits, the decision to lower class sizes brings the district in line with a new state formula that gives districts more money if they reduce their class sizes by the year 2020. Sacramento City Unified plans to add 75 teachers at 47 schools. Renee C. Byer rbyer@sacbee.com