Primary school students can tell when their schools are underfunded.
Henry Crofts, a teacher from Geelong in Victoria, once asked his students how they would spend money if the primary school received extra funding.
"They (say) we need new basketball rings, new netball rings - they want new line markings on our oval, shade sails, playground equipment ... sports uniforms - things like that," he told reporters in Canberra.
"They're aware of what they're lacking, but we don't have the money to adequately provide to the needs of our students."
In every jurisdiction, except the ACT, public school systems receive at least five per cent less than the amount required to meet student needs.
This means schools struggle to pay bills and many have been forced to combine students from different grades into the same class.
"We are only further entrenching inequality in our students and we cannot afford to give the least to those that need the most," Mr Crofts said.
South Australian year 12 student Madasyn Golding said underfunding could impact people's ability to learn, particularly if they came from disadvantaged backgrounds or lived with a disability.
"Students just don't have support from their teachers when they are covering so many people at a time," she said.
State education ministers, teachers and the Australian Education Union on Wednesday took to Parliament House and called on the federal government to take action.
Under the education agreement, the Commonwealth funds 20 per cent of the Schooling Resource Standard, which estimates how much total public funding a school requires to meet its students' needs.
Another 75 per cent should be paid by states and territory, though Victoria reportedly pays four per cent less because of accounting loopholes.
With this arrangement set to end, federal Education Minister Jason Clare has made a new $16 billion offer.
The Commonwealth has agreed to help fully fund the Northern Territory's public schools within five years by lifting its commitment to 40 per cent of the Schooling Resource Standard.
For every other state and territory, the federal government would increase its contribution to 22.5 per cent of the standard while asking the states to lift their share to 77.5 per cent.
"There are no blank cheques here. I want to invest billions into our public schools and I want to make sure that money makes a difference to our teachers and the students who really need it," Mr Clare said.
While WA has accepted this deal, education ministers from Victoria, NSW, the ACT, Queensland and South Australia are urging the Commonwealth to further increase its offer to 25 per cent.
NSW Deputy Premier and Education Minister Prue Car said her state could not roll out critical interventions at scale without more federal funding.
She said a GST carve-up that gives NSW $310 million less than it received in 2023/24 would make it difficult for the state to lift its contribution.
"We are in a worse position than we ever thought we would be," she told reporters in Canberra.
Victoria's Deputy Premier and Education Minister Ben Carroll and Greens Senator Penny Allman-Payne urged the federal government to address funding inequities as it pays at least 80 per cent of the Schooling Resource Standard for non-government schools compared to 20 per cent for public schools.
"(The federal government) needs to step up and show this country they actually believe in public education," Senator Allman-Payne said.
If the hold-out states do not sign on to the Commonwealth's increased offer by the end of September, the current deal will roll on.
