(Portland, OR) -- Classes are canceled again today in the Portland Public Schools district as the teachers' strike enters its second week. Today marks day four of the strike that began last Wednesday following months of failed contract negotiations between the district and the teachers union. Last week, the school district asked the state of Oregon to give it the funding it needs to fulfill the union's demands. The district says the teachers union is calling for changes that would cost 220-million dollars more than it currently has in its budget. The Portland Association of Teachers is demanding smaller classroom sizes and a pay raise of 21-percent over three years.