Friday, January 30, 2015

January 30 on Flying

Is there sufficient information to tell the time of arrival of this flight?

Thursday, January 29, 2015

January 29 on Kueh Bangkit

These moulds allow you to make three or five Kueh Bangkit in one go. Three persons were making Kueh Bangkit using these three moulds. 

After the first round, they made 13 pieces.

Is it possible for them to make 100 pieces after a while?

Wednesday, January 28, 2015

January 28 on Food We Eat

One bottle contains juice from 3 apples. How many bottles of juice can be made from 100 apples?

In The Times today, it is reported that landed needed to produce 1 kg of beef per year is 28.5 sq m, 1 kg poultry per year  is 7.1 sq m and 1 kg fruit and vegetable per year 0.5 sq m. 

What does this information tell us?

Monday, January 26, 2015

January 27 on Newspapers

I am beginning to miss Straits Times. In UK, I often read The Independent and it is interesting to see who is on Page Three.

Today it is Nicole Pusani who left her exclusive London restaurant chef job to cook in a school canteen.She was a top chef at Nopi in Soho. Now she cooks for 500 schoolchildren on a 92 pence per day per head budget.

Calculate her budget per day.

It is also interesting to follow the education news. "Its findings come as the number of schools converting to academies in the primary sector has now overtaken those in secondary sector - 2299 to 1884.However, because of the greater number of primary school, they are still in the minority in the sector whereas academies account for 60% of all secondary schools."

How many secondary schools are there? 

January 26 on Mugs

I collect these. 

I bought this for £6.95 each. What is the greatest number of this mugs that I can buy with a £20 note?

Saturday, January 24, 2015

January 23 on Coffee and Croissant

Three croissants and two cups flat white cost £10.60. Two croissants and three cups of flat white cost £11.40. 

a) What cost more - croissant or flat white?

b) Is this situation possible?

Location | Hej near Bermondsey Square in London 

Wednesday, January 21, 2015

January 22 on Strange Offer

Photo | Not By Me

In this store, one can of a drink cost $1.80. It also sold the drink at $5 for two cans.

If a customer who did not pay attention when his teacher was teaching mental mathematics took up the offer of $5 for two can, how many percent more did he pay than he needed to?

How many cans, at most, can a customer get for $5?

January 21 on Mosaics

I found this near Waterloo Station. Count the number of white mosaic pieces as well as the three layers of black ones. How can this be used to show that the circumference of a circle is about three times as long as its diameter?

Monday, January 19, 2015

January 20 on Plane Food

Simple Maths Airlines Need to Use

There are 14 seats on the lower cabin and 26 seats on the upper cabin where this fruit platter is served. 

How many watermelon balls should be packed in the box for upper and lower cabins, given that the airline packed 10% extra?

How many pounds or kilograms of grapes should be packed in the box for upper and lower cabins, given that the airline packed 10% extra? You may need to obtain essential information that are missing.

More Difficult Mathematics Airlines Need to Use

For TG910 from BKK to LHR, supper and breakfast are served. There are four main course options for supper and three for breakfast. The airline also wants to make sure each of the 40 passengers in this class of service get their choice. An easy but expensive way is to prepare 40 sets of each option but clearly it is wasteful to pack 280 sets for 40 passengers.

Propose the data needed for airlines to pack each meal option so that every passenger get his or her choice 95% of the time.

This is an example of a mathematics project where students do mathematical modeling. 

January 18 on Lockers

In Fitness First, shoe lockers are in rectangular arrangement. Lockers are numbered consecutively from top to bottom. 

Locker 201 and 195 are next to each other. The lockers are m-lockers tall.

Is it possible to find out the value of m with the given information ?

How tall, in cm, should each locker be? Explain.

Friday, January 16, 2015

January 16 on Gulps

A customer paid $37.10 for an odd number of cups of drinks - Gulp, Big Gulp and Super Big Gulp.

Find the number of cups of drinks the customer bought. 

January 16 on Pineapples

I went to Ang Mo Kio neighborhood stores and saw the fruit seller displaying his pineapples as shown in the photograph. The number of pineapples in a row is always one less than the number of pineapples in the row right below it.

The pile is four-pineapple high. The photograph shows part of the pile.

How many pineapples should be in the top row?

How many pineapples can be seen in the photograph if it had not been cropped to show only three of the four rows?

The pineapples are in an pyramid with the top cut off arrangement. Estimate the number of pineapples in such a pile. 

In order to display 200 pineapples in such a pile, how many pineapples should be in the bottom row? In the photograph, there are ten pineapples in the bottom row.

Thursday, January 15, 2015

January 15 on Boats

These boats used to transport goods up and down Singapore River. Today, it ferries tourists. Each boat have seats for 37 passengers. 

At an international conference, its organizers wanted to charter these boats to provide its participants with a tour on these boats. 

How many boats are needed, at least?

PS - Someone has spotted the missing information. The number of participants at the conference was 387.

A Little Bit of English and Science  |
Ali thinks that boats float in water because they are light. 

Explain why Ali is not correct.

Wednesday, January 14, 2015

January 14 on Goals

Based on the information in the photo, compare the number of goals scored by Ronaldo.

(a) Find the ratio of the number of goals headed in to the number scored with his left foot.

(b) Give a good estimate for the ratio of the number of goals scored using his right foot to that using his left foot in the form m : n where m and n are whole numbers less than 10.

Monday, January 12, 2015

January 13 on Coins

My colleague from National Institute of Education, retired professor, Dr Tan Wee Kiat, recently gave our school a hundred copies of his latest book on stamps and coins.

It inspired this problem, a typical upper primary word problem in Singapore school examinations.

Henry has some 10-cent, 20-cent and 50-cent coins.
The ratio of the number of 10-cent coins to the number of 20-cent coins is 7:2 .
The number of 50-cent coins is half the number of 20-cent coins. The total value of the 10-cent coins is $16 more than the total value of 50-cents coins.
How much does Henry have altogether?

Sunday, January 11, 2015

January 12 on Soccer

This graphics by The New Paper shows the different ways two soccer stars scored their goals in key tournaments in 2014. Pie graphs are used. The size of the two pie graphs should be different because Ronaldo scored 52 and Messi 49 goals. The area of a pie graph represents the number of goals.

(a) By how many percent should the radius of Messi's pie graph be reduced to make the graph correct?

(b) Calculate the average (mean) number of goals scored per game by each player. Explain the significance of this value.

(c) Calculate the number of minutes played per goal for each player. Explain the significance of this value. 

Thursday, January 8, 2015

January 9 on Public Transport

I usually take the taxi to the airport or get a lift / ride from a friend. Today I decided to try the bus and MRT (which is like the Tube in London or subway in New York or BTS in Bangkok). As a result I had time to take three random photo. 

Assessment Item (with technology) |

I left Balestier Road at 0620 and reached Changi Terminal 2 at 0715. The bus ride was 77 cents and train fare $1.21. By searching for further information on the internet, use ratio to compare (a) the cost of using a taxi to that using mass public transport such as the bus and the MRT (b) the time taken using a taxi to that using mass public transport.

In PISA and Common Core (in the US assessment) by two consortiums, technology has even infused into standardized testing. In the example above, students access the internet and have access to a calculator.

A Little Bit of English | Write a story using one or more of the photographs provided.

This is the new format PSLE writing test. Three visuals are given and student can write based on one image or two images or all three.

Wednesday, January 7, 2015

January 8 on Rats

The rat infestation in Bukit Batok has thrown a spotlight on the rodents. Here are the three common rodents found in Singapore. Source | The Straits Times January 8

Science and Maths Tasks |

(a) You are given a rat which is either the Norway rat, black rat or house mouse. Is it possible to use its mass or length to identify the rodent? Explain the method you plan to use to use.

(b) Based on the information given, estimate the least number of youngs an adult female house mouse can have in a year. Give you answer to the nearest ten.

Also estimate the greatest number of youngs it can have in a year.

Give an average number of youngs an adult female house mouse can have in a year.
Explain your method clearly.

A Little Bit of English | 
English Language
Explain the word 'infestation' and the phrase 'to throw a spotlight on'

Give three adjectives that describe rats.

Tuesday, January 6, 2015

January 7 on Average

Karamjit Kaur wrote an article related to an Indonesia AirAsia crash as 2014 came to a close. The unfortunate flight was on its way from Surabaya in Indonesia to Singapore. While we lost we only one Singaporean, we lost several who were closely connected to Singapore. A girl in one of our schools waited for her family who never arrived and a well-loved Biology teacher who taught in one of our junior colleges.

She wrote:

A spokesman for SilkAir, which operates a total of 64 weekly flights to 12 Indonesian cities, including Surabaya, Semarang and Medan, said: "As part of our standard operating procedures, Silkair files for landing and take-off slots from the respective slot coordinators, and then for approval from the relevant aviation authorities, before the start of every flight season. Approvals for our Indonesia routes are all in order." | The Straits Times 7 January 2015

Question | On average, how many flights per day does SilkAir have to each of the 12 Indonesian cities?

Discuss | Why is the value for the average less than one when number of flights have to be whole numbers? Can we say this is the average number of flights from Singapore to Indonesia? Why or why not?

A Little Bit of English and Science |

English Language
Take off is a phrases verb.
In this article, what does to 'take off' mean?
Give another meaning for to 'take off'.
Make two sentences to show the two different meanings of to take off.

What other phrasal verbs for take do you know?

A balloon floats in the air because it is light.
An aircraft with all its content and passengers is heavy.
What make it stay in the air?