Mexico City, Mexico — As Mexican children trooped back to school on Monday, they had already learned one lesson: You can't believe everything you read in your textbook.

Their new government-provided books are riddled with the sort of errors that students are supposed to be learning to avoid: misspellings, errors of grammar and punctuation, and at least one city located in the wrong state.

The foul-up is an embarrassment for a government that is trying to overhaul Mexico's much-criticized school system. Officials promised to give teachers a list of the errors so they can try to manually correct at least 117 mistakes. The Education Department acknowledged it found them only after 235 million elementary textbooks were already in the process of being printed.

"It's not fair. Children are impressionable. The moment they see the error, it stays with them," complained Edith Salinas, a graphic designer who had just dropped her sixth-grade girl off at school.

Education Secretary Emilio Chuayffet has called the errors "unforgivable," but he blames Mexico's previous administration for the stumble. He says he was faced with the predicament of choosing between stopping the printing of flawed textbooks so they could be corrected, and making sure the country's 26 million school children had textbooks for each subject at the start of classes.

Earlier this month, the Education Secretary pledged to find out who was responsible. He also gave the Mexican Academy of Language the task of ensuring that future editions won't contain such errors.

"How are we going to nurture minds with grammatical mistakes?" he said when he signed an agreement with the academy.

Still, Chuayffet's department has been less than transparent about just what the errors are. It had not released the list of mistakes to the public or even to the language academy members. The teacher's union also said it had seen no such list, and teachers leaving the classrooms on Monday said they had not received it.

The news blog Animal Politico did an independent review and found that words are misspelled in the Spanish textbook and accents forgotten or misplaced. There were words written with a "c" instead of an "s," common mix-ups that are taken as a sign you are not well educated. They have also found too many commas and words lacking the proper accent marks.

A geography text wrongly puts the Caribbean resort city of Tulum in the state of Yucatan instead of Quintana Roo, it said.

"Bad teachers, a bad state of education, and now bad books. Where are we going?" said Monica Lecuona, who was picking up her sixth-grade daughter amid a crowd of children weighted down with newly acquired textbooks at the gate of a school.

The scandal erupted in the summer and the rhetoric has heated up this month as teachers take to the streets to protest a sweeping educational overhaul that will submit them to evaluation and loosen the control held by their union over hiring and firing.

President Enrique Pena Nieto last week issued a package of rules for implementing the education law that was enacted in February. Angry teachers responded by blocking several major streets in the capital and causing a rush-hour traffic jam. The union promised more to come if legislators pass laws that mandate the firing of teachers who don't take or pass evaluation exams.

Political observers say the textbook scandal is a sign of the weakness of Mexico's education system.

Only 47 percent of the country's children graduate from the equivalent of high school. Mexico spends a greater share of its budget on education than any other member of the 34-nation Organization for Economic Cooperation and Development, but scores the lowest in standardized tests.

Experts say many teachers are unqualified, and under the old rules have been able to buy and sell their positions, which are relatively well-paying for Mexico's rural areas. At the same time, teachers point to a host of problems they have nothing to do with: class sizes up to 40 students, curricula that promote rote learning over engagement, and a lack of state money for maintenance.

The teachers now can add textbooks to their list of complaints.

Since the late 1950s, Mexico's "National Commission of Free Textbooks" has printed millions of books that are mandatory for both private and public schools.

Freelance editors who get paid less than $250 a month missed the errors in the new texts, commission head Joaquin Diez-Canedo said.

"The telephone rings, you have to go to the bathroom. You get distracted. You miss a word," he told the Mexican press.