One of the more disgusting things about today's toxic political environment is that we no longer fight just about winning but the core facts needed to hold a reasoned debate. That's what you get when part of the nation lives by Fox News and another chunk dies by MSNBC, I guess.

Fortunately, one area of government remains in which the facts are real and not easily dismissed. That's the facts around budget making, an annual exercise in which, like it or not, 2 plus 2 is still 4, and 8 times 3 remains 24. Which leads us to Mayor Lori Lightfoot's just-released 2020 city budget—and the latest on the Chicago Public Schools teachers strike.

Lightfoot amazed all sorts of folks—me included—when she rolled out an $11.65 billion spending plan without a property tax hike, save an $18 million boost in the separate public library fund. I give her honor credit for at least listening to all those people she met at her pre-budget hearings. The question is, can she count? The answer is: maybe. It depends on a couple of related queries.

The first is how much help Lightfoot will get from Springfield. Fortunately, the 2020 budget counts on little, just $50 million from a proposed hike in the real estate transfer fee. It should pass in the next few weeks, with an assist from Gov. J.B. Pritzker. Far harder to get through lawmakers will be revisions in the tax structure and maybe ownership of the proposed Chicago casino. But Lightfoot isn't counting on getting the hundreds of millions involved until 2021.

A little iffier is the $200 million she's counting on from refinancing city debt. The potential savings do appear to be there. But Lightfoot wants to book the entire savings in 2020, even though that money actually would be made over the 20-year life of the bonds involved. Call it "scoop and toss light," a form of borrowing. It may be necessary. That doesn't make it right.

A third question is whether Lightfoot really will deliver on the hundreds of millions of dollars of spending efficiencies she's promising, such as $150 million from zero-based budgeting. The answer won't be clear until she produces the promised list of where those $150 million in trims lie. But a 50 percent hike in spending in her personal office was, at a minimum, tone deaf.

Bottom line: Lightfoot's math could have been lots worse. It's too soon to say if it could have been much better.

As for the teacher talks, the most remarkable thing to me is that the Chicago Teachers Union continues to insist on its own set of facts, using math in, what, base 6?

The first example is its continuing instance that CPS got $1 billion in new money from the state for classroom needs. Wrong. It got some money, but a good two-thirds of that money was to pay old pension debt, and most of it came from a Chicago property tax hike—the very levy that was too toxic for Lightfoot to touch.

Example two is CTU's continuing instance that tax-increment financing pots, notably the $1.2 billion in subsidies allotted for the proposed Lincoln Yards megaplex, can be raided for school usage. Wrong—and for a simple reason: The money doesn't exist yet. It won't exist until Lincoln Yards is up and running and produces $1.2 billion in new property taxes, years and years from now.

The union would be better off trying to tap existing TIF districts with real money in the bank. But Lightfoot already does just that in her budget, declaring a $300 million TIF surplus, of which $163 million by law goes to CPS. CTU gripes that Lightfoot is clawing some of that back, such as $60 million for pensions for school workers who belong to a city retirement account. But what the union really wants is to zap "rich folks" and business by, for instance, reimposing a big head tax on jobs—the latter a nice way to declare that the only jobs that count are CTU jobs.

Yeah, I know it's tough. But unlike pols, math doesn't lie.