In September 2003, nine-year-old Marisol Rivera hesitantly entered Mary Wright's third-grade classroom at Sullivan Elementary School in Holyoke, Massachusetts. Early on, Marisol told Mary that she "hated math," and Mary noticed that during math Marisol often hid behind other students and avoided eye contact, which made it hard to determine how much she understood. Mary reflected on Marisol's participation in her class, but she wasn't sure what the problem was: Was it English? Was it math? Was it something else? What Mary was certain about was the need to rethink the way she was teaching the English-language learners (ELLs) in her class, especially the way she was teaching math.