A young Singaporean boy walked out of primary school final exams “crushed and defeated” by its math questions, prompting his mother to personally appeal to the education minister over the “unreasonably tough” questions.

Writing to Minister Ong Ye Kung online late Sunday night, Serene Eng-Yeo said her son had studied hard for the Primary School Leaving Examinations and even scored well on a preliminary exam.

“What is the point of making the paper so tough? Can [the Ministry of Education] explain the rationale behind this?” Yeo said in her Facebook post, adding that her son was not the only student who felt demoralized by the paper.

As of publication time, Ong had yet to respond.

The mother also posted images of some of the tough questions she alleges were posed to students as young as 11 in the exam, which is taken annually before students can move on to secondary school. The test has long been infamous for mind-boggling questions that even adults struggle to answer.

View photos Snippet of Serene Eng-Yeo’s post addressing Education Minister Ong Ye Kung. More

Check out the questions in Yeo’s post embedded below in case you’d like to have a go at solving them. Answers included at the end.

PSLE Mathematics question. More

View photos PSLE Mathematics question. More

View photos PSLE Mathematics question. More

The only education official to ever comment on the exam’s tough math questions was former education minister Heng Swee Keat back in 2013, when his ministry tweaked them in a way meant to better guide students while still maintaining high standards.

Six years later, students are still struggling with them, it seems. According to Yeo, the preliminary paper set by her son’s school was “humane” compared to Friday’s version by the Singapore Examinations and Assessment Board. Yeo said she had no doubt that her son’s school — which she didn’t name — would surely have matched the difficulty level of the board’s version if it had an “inkling” about how “crazy tough” this year’s paper would be.

Yeo said her son was “smiling” and seemed motivated after coming home from his preliminary examination, a stark contrast to how “crushed and defeated” he appeared walking out of the exam hall on Friday. He reportedly told her he was “dumbfounded by every question in Paper 2.”

Yeo went on to say that setting such tough questions can be detrimental to a child’s mental well-being, saying she could understand why some children took their own lives “when they cannot see beyond academics because Singapore has made [this exam the] be all and end all exam for the 12-year-old.”

Singapore has seen students commit suicide over examination results, including one case in which an 11-year-old boy fell 17 floors to his death in 2016 after failing his mid-year examinations for the first time, The Straits Times reported.

“And the joke is [that] no one cares what scores they get when they go out to work,” Yeo added.