What are they teaching in New York City preschools? At one taxpayer-funded Brooklyn nursery, it isn’t numbers, letters or nap time — but ­racism and victimhood, plus transgender and “queer’’ rights, with a heavy dose of political indoctrination in the mix.

“I was kind of horrified,’’ the father of a preschooler told me. “They say they’re trying to reduce racism and discrimination. To me, they’re perpetuating it, fomenting a sense of victimhood that 4-year-olds would never consider on their own.’’

In an e-mail to parents and caregivers on Jan. 16, teacher Rosy Clark lays out lessons based on the Black Lives Matter Week of ­Action for a pre-kindergarten class at PS 58, located in well-regarded District 15 in Carroll Gardens.

“This year, the week is Feb. 3-7. We are starting to talk about these ideas now, as we approach Martin Luther King Jr. Day [which was Jan. 20], and as we prepare to go into February, Black History Month,’’ teacher Clark, who is white, writes. The student population is also mainly Caucasian.

“I am lucky enough to work at this wonderful school where we strive to help our students understand the complex world around them and think critically about how they can participate in improving it. One of the ways I do that in my classroom is by exploring the 13 Principles of the Movement for Black Lives.’’

She explains that “I will not be discussing police brutality or current events with the class. These issues are obviously too traumatizing for this age group.’’

Some of the 13 points are unobjectionable — preaching diversity, plus acceptance and empathy, to children who, the dad argues, naturally love their neighbors.

Then there’s Principle No. 6: “Transgender Affirming,’’ Clark writes. “Everybody has the right to choose their own gender by listening to their own heart and mind. Everyone gets to choose if they are a boy or a girl or both or neither or something else, and no one gets to choose for them.”

And. No. 7: “Queer Affirming.’’ The principle here is that “everybody has the right to choose who [sic] they love and the kind of family they want by listening to their own heart and mind.’’

While most adults are fine with their children loving whomever they wish, introducing the loaded term “queer’’ to young ones is a deal-breaker, as is telling tots they can be any gender they choose, make up a gender — or possess no gender at all. These kids are too young to fully understand their own bodies, let alone gnostic gender ideology.

To me, No. 12 is also problematic: “Black Women.’’

“There are some people who think that women are less important than men,’’ the teacher writes. “We know that all people are important and have the right to be safe and talk about their feelings.’’

The teacher fails to identify these phantom fiends who devalue females, or “Black Women,’’ injecting division and suspicion toward pre-kindergarteners along gender lines, as well as racial ones.

At the end, she reveals her extracurricular work as an activist, work that evidently seeps into the classroom.

“Something that we talk about slightly less in the classroom are the national demands. These involve some more adult ideas and might come up occasionally in our conversations in small ways, but they are something that I really address in my activism work outside of the classroom.”

She cites a list of things she and her BLM cronies demand from schools:

“Hire More Black Teachers”

“Counselors Not Cops”

“End Zero Tolerance” [This aims to halt punishments, including suspensions and ­expulsions, for kids who commit school ­infractions, based on the idea that these penalties are handed out disproportionately to minority students.]

“Mandate Black and Ethnic Studies K-12’’

Phone messages and e-mails to Clark, as well as to PS 58’s principal, Katie Dello Stritto, weren’t returned. In an earlier ­exchange with a parent, the principal ­defended the curriculum as being in line with “Chancellor’s Regulations,’’ which dictate that a school must be a “safe space’’ for all students.

It seems instead that New York City schools, helmed by Mayor Bill de Blasio’s hand-picked chancellor, Richard Carranza, are transforming from educational centers into spaces in which activist educators may feel safe foisting far-left politics on impressionable children.