Unlike her peers, Cherrii Lim had little interest in television or computer games.
Instead, she loved dance, music, solving mathematics problems and wanted to be a doctor to help the world.
Even when the 12-year-old was diagnosed with acute myeloid leukaemia in February, she continued to log on to a maths portal to complete the daily challenges on an iPad.
The last challenge she completed was just seven hours before she slipped away on Sept 18.
Speaking to The New Paper, her father, Mr Daren Lim, a 46-year-old property agent, said this was characteristic of his younger daughter, whom he described as a "bubbly, lovely and just wonderful girl".
"Cherrii was always very focused in wanting to do her best. She was very good in maths and science, but she put a lot of effort in practising and practising every day," he said.
Cherrii had an elder sister, Carachel, 15, who is on the autism spectrum.
Multi-talented, Cherrii played the violin, ukulele and loved to dance.
When she first fell ill with a high fever on Feb 17, she insisted on going to school the next day so she could be in the Chinese dance performance for Punggol Primary School's Chinese New Year concert.
It would be one of the last days the Primary 6 pupil attended school.
Over the next 10 days, Mr Lim took Cherrii to two GPs, who prescribed her antibiotics.
But the fever would not subside.
On Feb 27, he took her to the accident and emergency department at the KK Women's and Children's Hospital, where she had a blood test.
It revealed that her white blood cell count was very high - a symptom of leukaemia.
Cherrii was immediately warded and started on chemotherapy the following day.
What came next was seven months of shuttling between the oncology ward and the intensive care unit. She never went back to school.
Of those seven months, because of her compromised immune system and the need for constant blood transfusions, she spent only two days out of hospital, her father said.
"She had a great fighting spirit and always thought she would recover and walk out of the hospital with us," he said.
In mid-August, doctors said Cherrii would not be able to survive another round of chemotherapy because she was too weak and asked her family to say their final goodbyes.
She went on to live another month, her father said, through sheer will.
"We also didn't tell her that her condition was terminal," he added.
Cherrii visited an e-learning portal by software firm KooBits, where students complete daily maths challenges for points. Competitive by nature, Cherrii would log into KooBits every day just to complete the daily challenge, Mr Lim said.
"It usually takes her less than 30 minutes to finish one round. But towards the end, she could only do (it) for 10 minutes before she had to take a break.
"The last assignment she did took close to an hour. But she finished it."
Cherrii's last assignment was submitted on Sept 17, just before 10pm. She died seven hours later.
In spite of her pain, she always tried to keep her spirits up.
A video posted on YouTube after her death showed a compilation of photos taken during her illness.
In a particularly poignant scene, Cherrii, bald from chemotherapy and in a hospital gown, is washing her hands. The moment she spots a camera, she starts dancing vigorously, an IV line dangling from her sleeve.
Mr Lim said that Cherrii lived with her grandparents in Hougang and would come back to the family home in Sembawang on weekends.
"Whenever she's around at home, she always tried to make everyone laugh," he said.
"She liked to eat seafood so we always went for that, or sushi, together. When she fell sick and couldn't eat prawns, she told me, 'Daddy, for the next five years, prawns won't be tasty to me. But five years later, it will be delicious again!'"
Father and daughter shared a special bond. Mr Lim would spend nights in the hospital with her. When she was in the ICU, he would catch a quick snooze on the benches in the common area.
It was a throwback to a happier time when Cherrii was born at the same hospital. Then, he also had to sleep on the benches because her delivery took more than 36 hours.
"I've had training," Mr Lim added with a laugh.
For now, there's little to laugh about at home, where Cherrii's ashes are kept in an urn.
Mr Lim stopped working in July to find alternative treatments for Cherrii and to take care of her.
Since her death, he has tried to keep his spirits up by going back to work but is finding it difficult.
"When Cherrii told me she wanted to be a doctor, I had motivation to work harder because I thought if she can't get into school here, at least I'll have money to send her overseas.
"Now that driving force is gone too," he said.
Yet there is a small silver lining.
"My wife and I are closer now, we talk more (compared to) when she used to just play with her phone in the car.
"But I still question why we were given someone so close to perfect who's been brutally taken away," he added.
A 'special' maths whiz
Cherrii Lim's former teachers and principal spoke fondly of the girl, whose favourite subject was maths.
A diligent student, she could solve challenging problem sums even at Primary 4, said her maths teacher, Ms Lim Gek Wah.
Calling her student "the special one", she added that after being introduced to self-directed learning on the KooBits portal, Cherrii was even more motivated to push herself further.
The teachers said Cherrii's classmates took the news about her illness in their stride and many even researched her condition to understand it better.
They made her "get well soon" cards, folded 1,000 origami paper cranes (a Japanese symbol of good health) and even created a blog where they could keep in touch with her.
The paper cranes, meant for when she made a full recovery, are now kept in a classroom and will be displayed in the Character and Citizenship Education corner in the school as a reminder of the values Cherrii displayed, said principal Hanafi Asmore.
Her story would also be shared during a school assembly session if her parents are agreeable, he added.
On Aug 8, 15 of her classmates and some teachers worked with the Make-A-Wish Foundation to throw a surprise party for Cherrii, complete with someone dressed up as a Minion - one of her favourite cartoon characters - from the movie Despicable Me.
She also dressed up as a doctor while her teachers and friends played her patients.
On Aug 28, Cherrii got another surprise when KooBits co-founder Stanley Han visited her in hospital to present her with two Top Brain of Singapore certificates.
These certificates are given out to the best performing student on KooBits for each quarter and Cherrii had won twice.
Despite being very ill, Cherrii visibly cheered up, Mr Han said.
What is acute myeloid leukaemia?
Simply explained, leukaemia is a cancer of the bone marrow, said Associate Professor Allen Yeoh, a senior consultant in the Division of Paediatric Haematology and Oncology at the National University Hospital.
There are several types of leukaemia, with the more common form being acute lymphoblastic leukaemia. In Cherrii's case, she suffered from acute myeloid leukaemia (AML) that may come about from a mutation in either white or red blood cells, or even platelet stem cells, Prof Yeoh said.
"It is more common in adults than children. AML is also more difficult to treat, very intensive cycles of chemotherapy must be administered to destroy the AML blasts over a short period of time," said Prof Yeoh, adding that only about 50 per cent of children with AML are cured with chemotherapy.
Cherrii had a complication with the FLT3 "growth switch" mutation. It is a gene that helps cells to grow, and a healthy person's body would be able to regulate when it is "switched on" or "switched off".
But with the FLT3-ITD mutation in Cherrii's case, it meant that the switch was constantly "on". Said Prof Yeoh: "AML cells with FLT3-ITD grow uncontrollably. Therefore AML patients with FLT3-ITD mutation have a more aggressive disease and a poorer outcome."
He added: "If we detect FLT3-ITD in children with AML at diagnosis, we would recommend bone marrow transplantation as part of the initial treatment as they have a high risk of relapse."
This article was first published on October 17, 2015.
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