Wages aren't the only reason teachers are striking

Schools in 39 of 50 states have seen decreases in funding for instructional materials for their students, according to data from the Urban Institute. These conditions have sparked a wave of teacher activism across the country.

Data: Urban Institute; Cartogram: Lazaro Gamio/Axios

Why it matters: Educators have had to pay for supplies themselves to provide new materials for students at times. Teachers' salaries aren't enough to pay for materials, either. In some cases they have to pay for materials for dozens of children.