Ang Kim Song took just five years to clear the PSLE, N levels, O levels and A levels, scoring a clutch of distinctions along the way.
He is no wonder kid blessed with exceptional smarts, though, but someone who came into the study game relatively late in life, when he was 31 years old. He sat and passed all those exams while in prison.
He had frittered away his teenage years and 20s taking and selling drugs, stealing and working for loan sharks, among other nefarious activities. "I regret I didn't study when I was younger.
Knowledge and education really opened my mind," says Mr Ang, now 37 and working in a social enterprise while pursuing a degree in mathematics at UniSIM.
His T-shirt and shorts spotted with wood dust, he leads the way to a canteen opposite Aestiwood - a woodworks company which hires former offenders and the marginalised - where he is project director.
His behaviour and mannerisms hint at an interesting past.
He uses a lot of Singlish, walks with a slight swagger and fields questions with a fearless albeit earnest candour, the mark of a man who has made peace with his past and feels he has nothing to hide.
His mother, a former Hokkien opera singer, is a hawker's assistant; his father was a drug addict who died in prison nearly 20 years ago. The couple divorced before their son was born.
Of his childhood, he says: "I saw my mother only three or four times a year. She was performing all over Malaysia with her opera troupe. My maternal grandfather brought me up. He sold fishballs in the market and we lived in a one-room rental flat in Bendemeer."
He was in kindergarten when his mother gave up performing and took a job at a hawker stall so she could look after him.
He was 10 when he first met his father, a hardcore drug addict who spent a lot of time in prison.
"When he was released, he contacted a friend and asked how he could reach my mother. My mother told me, 'You have a dad, you know. He wants to see you. Do you want to see him?' I was curious so I agreed. He took me out, bought me something and I never saw him again until I was 15, when I had already become bad.
He tried to give me advice but I said, 'So many years you never took care of me, now you want to talk to me? If you have money, we talk. If not, no talk'."
A former pupil of Beng Wan Primary, he was, he says, a good kid until Primary 3, when a classmate kept pestering him to play truant.
"I tried to avoid him but he was always waiting for me. He told me no one would know. And that was how I started playing truant to catch guppies in the drain," he says.
Things became worse when he got to know this friend's elder brother, a secret society member, and the latter's friends.
At 10, he picked up smoking. By 12, he was a glue sniffer who pretty much stayed away from school, only turning up during exams. "I was sent to the monolingual stream," he says, referring to the now defunct scheme which sent weak students to the then Vocational and Industrial Training Board (VITB) for technical training after Primary 8.
His behaviour so frustrated his mother that she sat him down and asked if he wanted to stay in school.
"I had a lot of older friends who were in VITB and they were all gangsters. I reckoned I'd probably end up a gangster as well so I decided to quit school in Primary 7."
For pocket money, he worked at McDonald's and other restaurants but these stints never lasted long. He was more interested in getting high by inhaling glue.
"I got arrested the first time when I was 13. I cried when I was put in a lock-up because I was scared. But after a while, I became a regular customer," he says, laughing. "The investigating officer knew me so well that each time he saw me, he would say, 'No need to take statement, just call his bailor'," adds Mr Ang, who was hauled up 20 times over a decade for glue sniffing.
Orchard Road and the old Marina South were his stomping grounds. He frequented tea dances at Fire and Canto, discos which saw more than their fair share of clashes between teen gangsters.
"In the 1990s, big gangs in Orchard Road would always want to swallow the small gangs. Fights would break out over nothing. Sometimes all it took was a stare," recalls Mr Ang, who was in a brawl involving more than 100 people outside Takashimaya in the mid 1990s.
At 16, he was thrown into the now defunct Abingdon Prison for two months. By then, he had graduated to marijuana.
That stay rattled him, but not enough to stop him from diving right back into drugs upon his release. "I went on to Ecstasy, which was becoming very popular. Because the drug was quite expensive, I decided to find some kang tau so I could make some money selling it," he says, using the Hokkien word for opportunities.
He took to theft, prising open lockers of stalls in Bendemeer market. Another short stint in prison followed. There were more drugs - dormicum, ketamine - and more stints in prison.
"Once, I had to meet a friend in Tampines. I didn't want to take a taxi so I decided to steal a motorbike. Unfortunately, there was a police road block. I tried to escape but the motorbike skidded and I fell," he says. It landed him behind bars for 11/2 years.
Each jail term hardened him a little more. "You become worse because you meet all these hardened criminals inside. I picked up boxing and other forms of fighting."
National service came next. But while most national servicemen passed out after 21/2 years, he took more than five years because of his drug habit, trouble-making and going Awol (absent without official leave) - he spent several stints of between two weeks and 27 months in the detention barracks or in jail.
He was 23 by the time he finally completed NS in 2003. He then found a job with a KTV lounge.
"I worked there for nearly a year, the longest period I held down a job. My performance was good, I was hardworking. Because the KTV lounge was expanding, the management needed good people who could help it manage new outlets. I was promoted after four months."
Things looked promising. His mother bought a three-room flat in Hougang, and he was giving her half his salary each month to help with the mortgage.
"I was still doing drugs but not as often as before," he says.
His promotion to supervisor at a new outlet in Cuppage Plaza, however, proved his undoing. "I started taking Erimin every day, because (it) made me happy and it helped me interact with customers."
It was not cheap. And since he had the key to the cash till and access to promotion vouchers, he hatched a scheme to cheat the company by misusing the vouchers and exchanging them for cash.
The management wised up, demoted him, and he left.
He then became a runner for a loan shark, and landed in jail two years later after a debtor worked with the police to ensnare him.
Released after five months in 2005, he became a cleaner but was arrested within a month because he smashed the windows of 51 cars to steal cash and other valuables.
Convicted of 12 charges, he was given eight years in prison in 2005. He was 27, and the stiff sentence finally made him re-evaluate his life.
"It struck me that I would be 35 and quite old when I got out of prison. If I carried on like I did, I would be like all the old men I saw who spent their entire lives going in and out of prison."
"I could probably even end up like my father who died in prison in 1997 when he was just 48 years old."
That year, he had spent more than a month with his father in the same jail - Queenstown Remand. His father had asked to be moved to a cell near him, and they would meet in the yard during exercise time.
"He would try and talk to me but I couldn't feel close to him," says Mr Ang, adding that he did not feel anything when his father died a few months later.
In 2005, with his long prison term stretching out before him, the hellraiser kept his head down and turned over a new leaf.
On a friend's urging three years later, he enrolled in the Prison School, starting classes shortly after Chinese New Year in 2009. His first test was the Primary School Leaving Examination (PSLE), then the N levels the following year.
"I took five subjects - English, Maths, Principles of Accounts, Combined Science and Theology - and scored distinctions in all of them."
His O-level results were equally impressive: four distinctions and a pass in English, and he had studied for additional maths on his own.
His biggest challenge was sitting the A levels. Because he was due to be released at end-2013, he had only one year to prepare instead of two. "I knew that if I did it after I left prison, it would be very difficult. I would not have the time or the teachers to help me," he says.
The odds were great, more so because the school did not have a teacher to help him with Physics.
But his will to succeed was so ironclad he managed As in Maths and Principles of Accounts, C in Physics, D in General Paper and a sub-pass in Management of Business.
It helped that the Prison School often invited speakers who motivated students and told them second chances awaited them.
"I refused to have any negative thoughts. I was not going to let negativity pull me down," he says.
Upon release in 2013, he applied to UniSIM to study mathematics.
"The National University of Singapore was out because I did not have any second language," he says.
A counsellor linked him up with Mr Darren Tan - a former inmate turned lawyer - who in turn connected him with community volunteer Patrick Chan, who has hired many former offenders for his businesses which range from woodwork to cleaning.
Mr Chan gave him a job at his woodwork company and agreed to finance his degree course.
Last September, Mr Chan decided to hand over the business to his staff and Aestiwood is now run by a team of four, three of them former offenders, including Mr Ang, who is the project director.
The former drug addict, who lives with his mother, says he is in a very good place now. He is doing extremely well in his course, and has made good friends at UniSIM.
And he has a girlfriend - a quality controller at a multinational corporation - and is tutoring two students in maths.
"I didn't know what I wanted in the past; that's why I was misled... I now have a purpose, I want to help other people, and I want to teach," says Mr Ang, who intends to continue at Aestiwood and teach at the Prison School when he graduates.
"I don't want to make my mother sad again. She has been sad too many times. She didn't give up on me. I'm doing this not just for myself but also for her."
This article was first published on August 23, 2015. Get a copy of The Straits Times or go to straitstimes.com for more stories.