# Maths Cafe

This is where you’ll find Bev’s latest thoughts, insights and relevant web links. As a Cafe, it’s a place for you to relax and browse. You’ll find interesting mathematics facts and snippets and helpful hints for making maths exciting and relevant. If you are a new subscriber it’s worth making a nice cup of coffee for yourself and checking out as many posts as you can – you never know what you’ll discover. Everyone can access this part of the website, even non-subscribers.

## How to use our Place Value Number Photographs

Maths Matters Resources is dedicated to helping you create real-life links in your maths classroom.

What are you trying to do?

- Use a real life example of number for a Place Value mental warm-up with your students

What do you need?

- Any of our Maths Matters Resources Place Value to 100 Photographs, such as house and letterbox numbers (e.g. on your electronic whiteboard).
- Any of our Place Value from 100 Photographs.
- Up to the whole class

What do you do?

- Talk about all the places you see real-life examples of numbers.
- Show the photograph e.g. 52. Ask the students to face a partner. On a given signal, each team has 1 minute to think of as many different things they know using that number as an example.

- “It is a 2-digit number, it’s larger than 50 but less than 100, it’s an even number, it’s a multiple of 2, 3 fewer than 55, half of 104, double is 26, 10 groups of 5 and 2 more, 52 is the age of my aunty, you could buy a pair of shoes for $52, 10 less than 65, that’s 10 pasta sticks plus 2 extra pieces of pasta, if I put 52 buttons into groups of 5 I would have 2 left over …”.

- At the end of the minute, discuss some of the discoveries with the whole class. Are there any misunderstandings?

Variations?

- Collect your own photographs of real life numbers for future mental warm-ups. e.g. How many different ways can you model this number? Beansticks, pasta sticks, Base 10 materials, groups of 10s and 1s pelicans, shells, alpacas (see our Place Value to 100 Photographs …)

- Use the photograph on an activity card or electronic whiteboard as part of a place value discussion with your students. e.g. Count by 1s, 2s, 5s and 10s to and from 52, try to add multiples of 52 – what’s the highest number you can reach?

## How to use the Maths Photographs

Any of our vast collection of Maths Matters Resources Photographs can be used as a suitable stimulus for your maths sessions. First identify the appropriate maths sub-strand. Next find a photograph that best suits your needs and the students’ interests.

For example, how will you use this picture of the 9 robots as part of your daily mental warm-ups? Ask everyone to brainstorm different maths ideas based on this photograph. Challenge them to be creative, to think of as many maths possibilities as they can. We need to develop maths confidence in our students so that they can think for themselves, without us always providing the mathematical links for them.

Stage 1 responses might be:

“one more makes 10”, “2 fewer will be 7”, “double these are 18”, “that’s 3 rows of 3”, “3 and 3 and 3 makes 9”, “there are 9 x 2 legs – that’s 18 legs”, “nine robots with 2 fingers on each hand makes 9 x 4 – that’s 4 less than 10 x 4 – that’s 36 – they have 36 fingers altogether”, “if I put them into groups of 4 there will be 1 left over”.

Stage 2 responses might be:

“4 groups like this would be 36 robots in total”, “if each robot costs $7 that would be 9 x $7 – that’s $63 to buy the lot”, “ if each robot has a mass of 80 grams that makes 9 x 80 – that’s a total mass of 720 grams or 0.72 kg”, “if you need 3 small balls to make each robot arm that’s 6 balls to make each robot, or 9 x 6 = 54 small green balls altogether”, “ if each robot displaces 50 mL of water, 9 robots have the same volume as 9 x 50 = 450 mL of water”.

Stage 3 responses might be:

“If it takes 3 robots 3 days to do a job, it will take only 1 day for 9 robots to do the same job because they can work 3 times as fast”, “if the area taken up by these 9 robots is about 20 x 20 cm, you will need a box about 25 x 25 cm and probably about 5 cm high to pack them in for sale in a shop”, “ if robot eyes come in packs of 100, you can make 50 robots”, “if they are battery-powered and each battery lasts for about 75 hours, you could get 9 x 75 hours of work out of them – 9 x 70 is 630 and 9 x 5 is 45 so that’s about 675 hours altogether”.

Congratulate students for specific maths suggestions using the photograph as an initial stimulus, such as the most mathematical links, the clearest example of a maths calculation, the quality of their discussion. The more specific they can be the better. Your students will soon look forward to inspiring you with their quick responses, depth of thinking and breadth of vision.

And of course you can use each photograph as part of your maths session activities – part of a smartboard discussion, a worksheet, an activity card, a group challenge question.

## Brazil World Cup Soccer Ball 2014

The traditional soccer ball is the 10th Archimedean solid – a truncated icosahedron. But times are changing! I don’t think there is an actual mathematical term for the latest ball, the Brazuca. Here are some interesting facts collected by Maths Matters Resources to help you integrate the World Cup soccer ball into your maths sessions.

Did you know that the special Adidas Brazuca, the Brazil 2014 World Cup soccer ball, was tested for over 2½ years? This name is slang for “Brazil” and was selected by a vote of over 1 million Brazil football fans. It has the smallest number of panels (6 identical pieces) ever, making it a very efficient design. Small dimples give it an irregular surface to create better aerodynamics. It was tried out by over 600 of the world’s top footballers. The colours symbolize the wish bracelets worn in Brazil. The actual ball is made in Pakistan and they have orders to produce over 42 million balls.

Imagine how you can integrate these facts into your maths sessions. For example, how much money will be spent if each ball costs at least $100? How many official games were in the World Cup tournament? How many times might one ball be kicked during one game? What’s the longest distance a ball can be kicked?

What’s your estimate for the surface area of this ball in square metres? Square centimetres? Do all soccer balls have the same surface area? How heavy is a soccer ball? What’s your estimate of the mass in kg?

What about other World Cup soccer ball facts? You can challenge your students to work in teams to come up with their own 10 interesting facts about soccer balls.

## Design a clock

Layla Mehdi Pour, a young designer from Iran, created this adjustable “Sophie” clock. Another designer from Britain designed a colour clock. Rnd Lab for Progetti designed what at first glance looks like a random clock. These can be the basis for a whole unit on Time. What sort of clock can your students invent? Normally we think of an analogue clock as round. What other shapes can they be? Do all clocks need a number? Why? Why not? Do they all need hands? Why? Why not? You could select a group of students to research clocks online and share one interesting clock each day of your Time Unit.

## Sharpen your imagination

Using real-life examples in your maths sessions will sharpen your students’ imaginations. Just like in this beautiful poster from Tang Yau Hoong. Encourage them to see maths in everything. A good start is to provide daily mental warm-ups using our maths photographs and maths graphics for mathematical brainstorms. Try not to rely on commercial textbooks and worksheets – these can stifle your students’ imaginations. Can they work with a partner to explain what they think and why? Maths language needs to pour out of them as they argue, explain, describe, compare and extend their thinking.

## Architecture and geometry

Of course architects create huge 3D geometric spaces all over the world. A wonderful source of investigation for primary students.

The 2014 Pritzker Prize for Architecture went to Japanese architect, Shiguru Ban. He created the temporary Cathedral for Christchurch, New Zealand, after the 2011 earthquake – made from recycled equal length cardboard tubes, wood and glass. These provided quick and efficient construction and the cathedral is large enough to hold 700 people.

Paper tubes are fairly inexpensive and Shiguru has used them for disaster relief structures in Ahmedabad India, Rwanda and Kobe, Japan. Imagine what your students could create using cardboard tubes, just like this prize-winning architect.

## Data investigations with large numbers

In 2013 The Rolling Stones earned $26 215 121.71. A pretty large number. Your Stage 3 students can discover amazing large number facts hidden behind their favourite pop groups. Long ago, my favourite group was the Rolling Stones. I was fascinated to see that in 2013 they still earned so much money. What are the 10 favourite pop groups in your class this year? How will they find out? Who will collect this data? How much did each of these groups earn last year? How do you know? How will you find out? Who will do this? Can they estimate first the order for the top 10 earners? Once you have your ten $ amounts you can put them into ascending or descending order, find the $ differences between the 1st and the 2nd highest earners. You can also create a column graph – what will the scale look like? Why? What will be the title of your graph?

Challenge your students to create further mathematical questions e.g. Who is the highest earning pop group of all time? Who is the highest earning individual performer this year? Ever? Who is the highest earning musician this year? Ever? Do pop stars earn more than other musicians?

## How to use the People Photographs

Any of our People Photographs can be used as a suitable stimulus for your maths sessions. Look through the collection and find the photograph that best suits your needs and the students’ interests. For example, show the picture of the ballet dancer. Ask everyone to brainstorm 10 different maths ideas based on this photograph. Challenge them to be creative, to think of as many maths possibilities as they can. We need to develop maths confidence in our students so that they can think for themselves, without us always providing the mathematical links for them.

How many right angles can you spot? Acute angles? Obtuse angles? Reflex angles? How long can a dancer stay on their toes? What is the longest time on record? Look at her hair – how long might it really be? Why has it been tied up so tightly? Who are the 10 most famous ballet dancers in the world today? Why are they so famous? Who is/was the most famous ballet dancer ever? How do you know this? How many students in your class are learning ballet? What percentage is this? What would it look like as a column graph? What is the ratio of boy to girl ballet dancers in your class? What is the ratio of ballet to non-ballet dancers in your class? How many times can a dancer spin before they lose their balance? What’s the longest time a dancer can stand on just one foot? How much does a pair of ballet shoes cost? What is the most popular form of dance? How will you find out?

Once you have a suitable collection of questions, these can then form the basis of further class investigations, or problems to solve. Teams can select the question they most want to investigate. Again challenge your students to find as much mathematics hidden in their topic as they can. You can always use the Maths Sub-strand Checklist proforma as a prompt for their thinking. You can find this in the first column (General Info).

Congratulate students for specific maths achievements using the photograph as an initial stimulus, such as the most mathematical links, the clearest example of maths calculations, the quality of their presentation details.The more specific they can be the better. You don’t need lots of worksheets and textbooks to stimulate your students in maths. You need something that excites their interest, that intrigues them, that encourages them to ask more questions.

Try to make time at least once each week to use a photograph as a quick mental warm-up. Your students will soon look forward to inspiring you with their quick responses, depth of thinking and breadth of vision.

## 3D and 2D Reflections

Reflections are part of the Geometry strand in Primary Mathematics. Being able to visualise what something looks like along an axis of symmetry is more difficult than you think. Spatial visualisation skills are used frequently in our daily life and we need to practise reflecting or flipping images in a variety of ways. Flips can be in any direction. These zebras are flipped across a horizontal line formed by the waterhole. A vertical flip would create an entirely different picture. How can you encourage your students to flip images both mentally and by using pieces of silver cardboard or a safety mirror?

## Looking down from above

Looking down is an essential skill in Position/Location, a sub-strand of Geometry. Your ability to imagine things from a different perspective helps you solve problems. Close you eyes and think of a 3D object. Now try to see it from above, from the left side, from below, from the right side, from behind. What will it look like in these different positions? What looks the same? What looks different? Very few people get to see the famous Uluru from above. The rock is now not instantly recognisable as an icon of Australia. Most people can only recognise Uluru from its side-on position seen from ground level. How can you help your students develop this skill through a daily Mental warm-up?

## World population statistics

Lego mini figures were created in 1978. By 2019 there will be more LEGO mini figures than humans in our world. That’s more than 8 billion plastic figures. Amazing.

How can world populations inspire your students? Do you regularly look at world population counters? You can easily set up one on your class computer and challenge your students to suggest maths facts, problems and related or inspired thoughts daily.

For example, Worldometers gives access to a wide range of population statistics for daily analysis.

## How to grow the best sunflowers

Growing sunflowers in your school garden is a great way to investigate real-life maths.

Here are some useful hints to help you grow the best flowers:

- Find a well-drained garden patch.

- Dig your garden to a depth of about 50 cm.

- Use a slow release fertilizer like Ozmocote.

- Sow the 5 seeds in a clump to a depth of 3 cm and cover with soil.

- Plant each clump 50 cm apart.

- Water lightly and keep the soil moist.

- Seedlings should appear in 5 – 10 days.

- Remove the weaker 1 – 2 plants in each clump when they are about 10 cm tall.

- Leave just the best 1 – 2 plants in each clump when they are 30 cm tall.

- If necessary, remove any extra plants to leave just one plant in each original clump at about 50 cm.

- Enjoy looking after your sunflowers and watching them grow.

For plenty of ideas on using real-life Sunflower Maths activities with your students, see the Sunflower Maths Sprouts in Sneak Peek.

## 2D Flag Investigations

Flags are packed with amazing real-life maths. The patterns and colours, the symbols and, of course, the shapes. The vast majority of flags in the world are rectangular. You can investigate the ratio of the shortest to the longest side. Some are in a 1:2 proportion, like the Australian and British flags, or a 2:3 proportion, like the French, Italian or Spanish flags. Qatar holds the record for the largest flag in area, covering 101 978 square metres. It was created for their National Day in December 2013. It had a mass of 9.8 tonnes too. Afterwards, it was recycled into 200 000 satchels for school children. The longest flag in the world was created in Syria on 10 July 2011. It was 16 km long. And in Bangladesh, 27 117 volunteers holding up red and green blocks created the largest human flag on 16 December 2013. Then of course there is the only non-quadrilateral flag in the world, the Nepalese flag. It’s a pentagon.

Imagine what facts your class can collect to astound you, visitors and parents alike.

## Budgerigar facts

Did you know that budgerigars can turn their heads 180 degrees and fly over 100 km in search of water? Real-life mathematics can be found everywhere. Each group of students in your class could investigate a favourite animal or bird and create 10 top maths facts to tantalise their classmates. Create class Maths Facts books to browse through regularly. Challenge your students to construct 3 extended maths questions based on one maths fact as a daily mental warm-up. e.g. Can all birds turn their heads 180 degrees? If not, which other birds can? Why would this be a useful skill? The idea is to encourage students to think for themselves, to see how to ask a maths question as an active participant, not just a passive listener, or a passive answerer of someone else’s question.

## Checking the length of a swimming costume

Look for examples of real-life maths from the past. Both teachers and students enjoy reflecting on life long ago. This example shows a beach inspector in America measuring the exact length of a swimming costume. It had to be no more than 6 inches away from the knee. Imagine if they still had to measure this today!

## Population Graphs

There are so many different ways to create a graph. You want to communicate your key point as clearly as possible. These 2 graphs created by Bill Rankin from Yale University in 2008 show how our world population looked in 2000 when sorted by latitude into north and south hemispheres. The graph shows that about 88% of us live in the northern hemisphere. On average the world’s population lives 24 degrees from the equator. When sorted by longitude it shows that most people live up to 180 degrees east of Greenwich. What are some different ways you create graphs in your classroom?

## Magnetic Termite Mounds

The huge magnetic termite mounds at Litchfield National Park, Northern Territory, are perfectly aligned north to south to minimise the exposure to sun. This brilliant architectural feat keeps the mound at exactly 30 degrees C. They include arches, tunnels, chimneys, insulation and nurseries. Challenge your students to discover other creatures that use NSEW orientations in their daily lives. How do the 4 major compass points effect your life?

## The longest married couple in the US

Ann and John Betar are currently the longest married couple in the US. They were married on 25 November 1932. That’s 81 years. The record for the longest married couple is Karam and Katari Cham in Bradford, UK. They were married for almost 88 years. Your students can create a table recording their grandparents’ marriage records. When was the earliest marriage for grandparents? When was the most recent marriage? What are some questions they can ask? What can they discover by looking at the data in this table?

## Sculpture by the Sea

Every year for the last 17 years, Bondi has hosted Sculpture by the Sea in October /November. It began as just one day and now lasts over 2 weeks. It is a fantastic opportunity, if you can get to Sydney, for your students to view and discuss their reactions to over 100 sculptures.

The sculpture shown here is Horizon by Lucy Humphrey.

If you are not able to get to Sydney for this event, there are plenty of photographs online. You can also see the exhibition at other times of the year at Cottesloe, Western Australia and also Aarhus, Denmark.

## The importance of estimating

Remember that it is often more important for your students to be able to estimate effectively than to calculate accurately. Encourage them to find strategies to help them estimate each day. For example, one strategy might be to visualise breaking up a large quantity into tenths. Roughly work out how many in that tenth and then multiply by 10 to get your estimate. How many bananas do you think are in this pile? How does your estimate compare with a friend’s estimate? Is it in the right ballpark? How do you know?