1, 2, 3, 4, 5 Math Qn

Someone needed help with the following question:
The digits 1, 2, 3, 4 and 5 can form 120 five-digit numbers, each without any repeating digit. What is the sum of these 120 numbers?

Solution by Lim Li:
Each of the digits 1, 2, 3, 4 and 5 appears 24 (i.e. 120/5) times in the Ones, Tens, Hundreds, Thousands and 10 Thousands place.
1+2+3+4+5 = 15
24 x 15 = 360
Hence,
+++++360
++++360
+++360
++360
+360
------------
=3999960 (sum of all 120 numbers)
------------

Mathlinks aka Art of Problem Solving

This is posted by LJ's mum.

Mathlinks is a website/forum that Lim Jeck frequents, on an almost daily basis. It is where he hones his Maths Olympiad problem solving skills. Since joining Mathlinks on 10 March 2010, he has contributed 760 posts (as at 25 January 2011) which works out to an average of 2.73 posts per day. Out of a total of 78,927 members, Lim Jeck aka oneplusone is currently ranked the 455th most active user. The most active user has to-date made 12,301 posts in the various forums!

He also participates in an unofficial Olympiad Marathon initiated by a fellow forum user. Currently, he is ranked 1st, after some 14 rounds of questions.

Cut the Rope HD (iPad game)

We are currently the top in national and local for the Cut the Rope game in Cardboard, Fabric and Foil box leaderboard categories, with scores of 140240, 137120 and 132890 respectively.

Cut the Rope is a strategic game that tests your puzzle solving skills. There is this cute fat round green monster, Om Nom, who has a penchant for candy. The objective of the game is to bring the candy to Om Nom's mouth which is almost as big as him. If the candy is attached to a rope, you can "Cut the Rope" with your finger. To complete a level, you need to decide which ropes and when to cut, to swing/drop/float/etc the candy into his mouth, collecting as many stars as possible in the process.

We have aready completed the game and have nothing much to do as I am too "sian" to achieve national tops for the gift and cosmic box.

Funny Photos from Newspapers

Professional Photography?!

From The Straits Times - Feng Tianwei, who rescued Singapore from quarter-final exit during the Asian Games 2010.

From My Paper - Monaco's Princess Stephanie was in Singapore to support her daughter, who participated in the inaugural YOG 2010.

2000th 7-digit Math Question

Someone posted the following question:
All the 7-digit numbers containing each of the digits 1, 2, 3, 4, 5, 6, 7 exactly once, and not divisible by 5, are arranged in the increasing order. Find the 2000th number in this list.

Solved by Lim Li ☺☻:
Since the 7-digit number cannot be divisible by 5, the last digit cannot be 5.
If the 1st digit is fixed, there are 1x2x3x4x5x5 = 600 numbers
[1]765432 => 600th number
[2]765431 => 1200th
[3]765421 => 1800th
If the 1st and 2nd digits are fixed, there are 1x2x3x4x4 = 96 numbers
[41]76532 => 1896th
[42]76531 => 1992nd
:
[4312]756 => 1996th
[4315]267 => 1997th
[4315]276 => 1998th
[4315]627 => 1999th
[4315]672 => 2000th
Hence the 2000th number is 4315672

A Busy Year for 2011 ...

This is posted by LJ's mum.

2011 is going to be a very busy year for the kids.

For Lim Min, she is going to RI. While she takes about 20 mins to travel by MRT & bus to RGS, she will now need to spend about 40 mins to travel to RI (Queenstown MRT to Marymount MRT). I heard from ex-RGS now-RI parents that students are much busier in RI and they have to take 2 CCAs, which means they work harder and play harder as compared to when they are in secondary school! Lim Min will be taking GP and 4 H2s - Maths, Physics, Chemistry and Economics. She has done very well for her Maths (scoring 98 & 100 for the Maths 1 & Maths 2) and 3 Sciences (scoring 90 or close) while in RGS so it's a pity that she has to drop Biology to take the contrasting subject, Economics. But I heard Economics is an interesting subject so I guess, you lose some and you gain some.

For Lim Jeck, he is going to have an incredibly busy schedule! He is taking two NUS modules - Linear Algebra from NUS Faculty of Science and Competitive Programming (this module is free and ungraded) from the School of Computing. On top of that, he has the usual National Team Training at NUS Math Dept on Saturday mornings. Including the NUS modules, I think his timetable will have 2 days that end at 6 pm, 2 days end at 7 pm (Linear Algebra, 4-7 pm) and 1 day ends at 9 pm (Competitive Programming, 6-9 pm). He did well for his previous NUS module - Calculus and got an A+, which means he is able to claim the bulk of the course fee from NUS High. I think NUS High really suits him to a T, as he can enjoy working on his passion while maximising his potential in his strong areas - maths, physics, chemistry and programming.

For Lim Li, next year is PSLE year. Needless to say, she will have to stay back in school most of the days and her school teachers are going to give her tonnes of homework in preparation for the PSLE. She should have no problem doing well for Maths and Science, but I think she has to put in more effort for English and Chinese, her weaker subjects. I am sure her Chinese teacher, Ms Chai, will do the necessary to prepare the class well, so Lim Li should do all right (hopefully, get a high A) as long as she does all the work assigned by Ms Chai, diligently. I am more worried for her English. Maybe I would work out a schedule to revise English with her.

Hope everyone can have a fruitful year ahead!

Hikaru No Go

"Hikaru No Go" is a Japanese comic manga series as well as anime. It is our family favourite, as even my parents also read the comic books and watched the DVDs which we borrowed from the libraries. It also piques our interest in the Go game, which we are playing now :)

Hikaru No Go is the story of a 6-grader, Shindo Hikaru (left on above picture: boy with yellow hair), who by chance meets a 1000-year old ghost, Fujiwarano Sai (right on above picture: man with almost lady-like features) , who was trapped in a Go Board before his release. Together, Hikaru Shindo and Sai make a great go-playing team and they follow the path that leads them to the divine move or "Hand of God"; along the way they meet many memorable characters, such as Waya, Isumi, Ochi and Hikaru's and Sai's respective destined rivals, Touya Akira and Touya Kouyo.

There are many touching scenes such as those depicting the close friendship ties fostered between Hikaru and Sai, as well as among the the group of friends as they graduate from Insei to become Pro, or professional Go players, the integrity conflict and how a depressed Hikaru goes searching for Sai when he leaves suddenly. This is definitely a manga which I would recommend to anyone, even if you don't play Go.

3N Royal Caribbean Cruise

My family went for a 4 Days 3 Nights Best of Malaysia on Royal Caribbean Cruise (Legend of The Seas) from 20 Dec to 23 Dec. We stayed in 2 rooms, Oceanview stateroom, Deck 2. It was a relaxing and enjoyable trip, with lots of fun games, rock climbing and delectable food. We also joined the shore excursion to Penang - visit to butterfly farm, SEA's longest bridge, kampongs.

Playing table soccer.

Playing wii.

Endless supply of twist ice cream.

Lobster and elephant made by our stateroom attendant.

Towel folding class where we learnt how to fold tortoise, dog, elephant and monkey.

We enjoyed rock climbing.

Fine Dining at Romeo and Juliet restaurant, with starter, main course and desserts (which we shared).

Our favourite hang-out place - the Optix (Deck 10), where we played table soccer, wii and card games.

My Cousin's Wedding

Extended family group photo taken after my cousin (Han Kee)'s wedding banquet at Ritz-Calton, on 12 Dec 2010.

Top in Singapore for Froggy Jump

Lim Li is now officially the top scorer in Singapore for Froggy Jump, with a score of 2,071,984. The 2nd highest score in Singapore is 1,152,708. The world's highest score is 67,116,504 (by someone in USA), and Lim Li is ranked 223rd in the world.

The above shows the locations of the top 6 scorers in Singapore.

And of course, the top scorer lives in Queens!

Comic Books

Comic books which we devour during the school holidays. Every week, we read 20-30 books. All were borrowed from the Central Public Library and Jurong Regional Library.

My Favourite Comic Books

This is posted by LL ☺☻ 1st - Case Closed

2nd - Fullmetal Alchemist

3rd - Skip Beat

4th - Shaman King

5th - Hunter x Hunter

QPS 6A'06 Gathering on 29 Nov

Gathering for Lim Min's primary school classmates, at Queens function room.

No one is supposed to know how this game is played.

With Mr Tan looking on. Both Mr Ng and Ms Chai could not make it for the gathering :(

Playing card game with twisties as bets?

Lim Li joining the current Sec 4s for a card game.

NUS High 1-Day Math Camp

This is posted by LL ☺ ☻

Yesterday I attended a Logic and Games Math camp at NUS High. At the camp, there were only 3 girls out of 18 students, so sad.

We played the frog puzzle, the one where the frog can only walk 1 step or jump over another frog. We must find the formula for the number of moves depending on n number of frogs, which is n^2+2n. Other games we played include: Nim, Cross the River, Quadrant tic-tac-toe, etc. The student helper Ananya Kumar said that Lim Jeck had been blabbering about minecraft for the past 3 days and Lim Jeck said that the graphics was great (the sun, moon, stars, clouds and hands are squares and everything is pixelated ☺).

At lunch, the food was not buffet kind, but a packet of bee hoon with egg, fish, otah, fish cake and ikan billis (see picture). For tea breaks, we had packets and biscuits. So pathetic right ... actually, not so bad, I am just exaggerating and I brought home 4 packets of drink and a lot of biscuits until my bag was so full that I could not put my pencil case inside and I had to put it in my pocket.

I think the camp is quite fun.

QtPS Year End Prize Giving Ceremony

This is posted by LL's mum.
This year the EOY Prize Giving Ceremony is held at night (7.30 pm) instead of in the morning (as in previous years). There is also a cultural night performance after the prize giving ceremony. Lim Li gets two awards - Top in Maths and Top in Science. She wants to apply to only NUS High for DSA next year, and has no intention to try other schools like RGS and NJC. I think NUS High is probably suitable for her :). Like her two older siblings, she is stronger in Maths and Science and weaker in the languages.

Froggy Jump - ranked 3rd in Singapore

This is posted by LL.
My score for Froggy Jump is 1,070,532. I am ranked 3rd in Singapore and 592th in the world. Aren't I pro? The current highest score in the world is 67,116,504.

The top score in Singapore is 1,152,708. I think I could have easily beaten this record if I had not given up after playing for more than 1 hr and getting very "xian". I thought the top score is 500k+, otherwise I would have perservere to earn the top spot. So wasted!!!! My feeling now is opposite of this ☺

Bakegyamon

This is posted by LL.

School holidays are around the corner, it means we can read comic books to our hearts' content. Recently, we borrowed this Bakegyamon book from the Jurong Libary. There is only 1 of this English comic title in the Jurong and Central Libary and it is only until volume 3. However the Chinese version has all 5 volumes.

The story is about Sanshiro (the red-cap boy), whose father is an adventurer and he wants to follow his father's footsteps. So a guy called Fue (beside Sanshiro in the picture) brought him to play Bakegyamon, a game that comes every 44 years for thousands of children to play and the winner will get 1 wish granted. Demons are turned into cards (Sanshiro is holding it in the picture) for the players to use to fight. Many players think that the demons are items but they are not. Being a kind and considerate boy, Sanshiro decides that his wish is to free the demons, if he wins the game.

Exams .. not over yet!

Today I have taken the make-up paper for English.

The last exam paper is on 22 Nov - Calculus.

Spinning Table

CWMO Photos

Wayne, Wei Liang, Zhan Xiong, Mr Teo, me, Ding Yue, Ryan Kor, Joseph Kuan

Two burly "bodyguards" protecting Ryan and me.

Yema Rallygraf watch (branded??) for Gold medalists. Why didn't they give computer notebooks, like what Kazahstan did in this year's IMO, for the Gold medalists?

Remember Lim Min's CGMO photos? Déjà vu

Singapore won 2 Gold medals and 6 Silver medals, same as last year.

We were compensated S$100 each :) for the 6 hours' delay in the flight from Singapore to Shanghai