It was only during his third stint in prison that Alex finally focused on his studies.
Two years into an 8 1/2-year sentence he received in 2009 for drug offences, he hit the textbooks for the first time since he was in Secondary 4.
Now 32, Alex (not his real name) emerged as last year's top A-level student at Tanah Merah Prison School when the results were released last Monday.
He scored As in mathematics, principles of accounting and mother tongue, and B in business management and economics.
He got a D for General Paper.
This has given him the confidence that he can do more for his mother than just help out at her noodle stall after his release.
"Now, I can even think about expanding it... I have a bigger dream now."
Alex was one of 20 candidates who took their A levels in prison last year. Eight inmates scored passes in three H2 subjects and General Paper.
Admission to Tanah Merah Prison School - the only such school in Singapore - is based on the inmates' academic qualifications, their conduct in prison, as well as recommendations from supervisors and superintendents.
Now it has an enrolment of 290 students - with 32 per cent taking O levels, and 12 per cent preparing for A levels. Other courses include English literacy and primary school-level programmes.
The school has its own cells, and lessons are conducted in classrooms from 8am to 3pm. It has 15 teachers seconded from the Ministry of Education, along with part-time teachers and volunteers.
Mr Lee Chee Khuen, who joined the prison school in 2009 and teaches accounting and economics, said the job has been very rewarding.
Inmates have made him cards and "thank you" notes to show their appreciation.
"I see myself as being part of the inmates' rehabilitation journey and I am happy when they do well and turn over a new leaf," said the 53-year-old.
The inmates' personal supervisor, prison officer Corporal Peranban Kumar, also described how they are willing to sacrifice their leisure time for extra studies, and help one another.
"John" - sentenced in 2009 for unlicensed moneylending activities - is another inmate who took the A-level exams last year.
In his younger days, he was suspended from secondary school, failed his O levels and dropped out of the Institute of Technical Education after just three months. He job-hopped but struggled with a gambling addiction.
The 33-year-old scored As for principles of accounting, mathematics and mother tongue, C for General Paper, and Ds in economics and management of business. Now, he is considering starting an online business after his release.
Meanwhile, Alex will soon apply to enrol in university, something that he never used to consider.
When he was in Secondary 2, he worked part-time in a fast-food restaurant to ease the burden on his mother, the family's sole breadwinner.
"I always thought my mother would rather I work and earn money for the family than study," said Alex, whose three siblings have O-level qualifications.
He did two stints in jail, one of them due to a drug-related offence.
When his third jail term began, he had considered enrolling in the prison school, but was put off by his age and a lack of confidence.
"It had been more than 10 years since I last studied," he said. But his mother encouraged him to sign up, reminding him how he used to do well in maths.
"She said I was the only one in our family who was close to getting a degree and I should not give up."
His mother does not know how well he has scored this time.
Alex and other student inmates will get to share their results with loved ones in a rare open visit this week where, instead of being separated by a glass panel, they can share hugs.