Even a bad high school student knows that you drive up costs when demand soars and you decrease supply.

That is the reality facing President Donald Trump and retirees as his moves to reduce the number of immigrants in the nation are destined to shrink the supply and drive up the price of home-care aides for the nation’s seniors, say industry experts.

For retirees who won’t be able to find aides because of the crackdown, Trump’s actions could force them out of their homes and to spend thousands more a month for assisted care and nursing facilities.

While costs can vary widely, assisted living centers generally cost from $4,000 to $6,000 a month and nursing homes in the $6,000 to $10,000 range, according to the National Association for Home Care & Hospice.

By contrast, home health aides can cost far less, especially if continual coverage is not required.

While the Trump impact on home health is just beginning, legal Latino and Muslim nurses are in hiding because of the immigration raids, said Abigail Zapote, executive director of Latinos for a Secure Retirement.

About one in four home-care aides are documented and undocumented immigrants, estimates the Paraprofessional Healthcare Institute.

“Trump’s immigration policies are aggravating the crisis in home-care giving,” said PHI Vice President for Policy Robert Espinoza.

The crisis is exploding because of a double whammy, a PHI Policy asserts. On the demand side, the number of Americans 65 and over is projected to nearly double in 35 years to 88 million and about half of them will need some kind of long-term care.

On the supply side, the pool of the primary workers in the industry, women 25 to 64, is anticipate to rise by only 1 percent.

Half of home-care workers leave the field within 12 months because of low wages and hard work.

Trump is creating an environment that could scare off both would-be documented and undocumented home aides from entering the nation, cautioned National Association for Home Care & Hospice Vice President for Law Bill Dombi.

Dombi said the only alternative for seniors who can’t afford to pay more for home health and assistance in shopping, bathing and cleaning may be to get fewer hours of help a week -- and a lower standard of living.

He added wage increases resulting from the shortages could lead some companies to stop providing home nursing assistants for seniors who are getting their care from low fixed-rate hourly schedules from Medicaid and the Veterans Administration.

Home-care aides often are paid $10 an hour, but training and Social Security and other costs raise the fee his members must charge to around $15.50. Add health care for the employees and the fee goes to $17.50. In the Northeast, many home-health agencies charge at least $20 a hour.

Phil Bongiorno, executive director for the Home Care Association of America, whose members specialize in aides who provide in-home help outside of nursing, warned there could be shortages and price increases if the number of worker visas is not expanded.

Like Trump, who has promised to build a wall that could keep potential aides away, Caring Senior Service founder and Jeff Salter was blunt.

“Trump’s immigration policies will greatly decrease availability. In order to maintain our standards in regards to the level of care we pride ourselves in providing, we will likely have to increase our rates,” said Salter, whose 49 franchises and three company-owned operations offer home care assistance for everything from meal preparation to errands.