School has only been in for a few days but parents have already started receiving fundraising requests from their children's schools.

All week, CBC Calgary is investigating the pressures on the city's public school system as part of the series Education Inflation.

Here are seven things to know about school fundraising in Calgary.

1. More than 30 public schools in the city have no parent society so they can't fundraise at all. Most of these schools are in less wealthy neighbourhoods.

2. Money that's fundraised from parents can be used to buy physical education equipment, library books, iPads, Smart Boards and other technology. It can also pay for field trips and other enrichment opportunities.

3. That money cannot be used to hire extra staff or to hold parties such as school dances.

4. Springbank Middle School recently hired a professional fundraiser to help raise $3 million for a new gymnasium and other building upgrades.

5. Casinos are the largest source of fundraising for schools, bringing in approximately $60,000 every other year. You need nearly 40 parents to volunteer at the casino so not every school can participate.

6. The Calgary Catholic School District no longer fundraises from gambling, including casinos and bingo nights. It's estimated that its schools used to raise $2 million per year from gambling events.

7. There is a fund through Education Matters that allows schools in wealthy neighbourhoods to donate a portion of their fundraising to schools that have trouble raising money.