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Four Go

This challenge is a game for two players. Choose two numbers from the grid and multiply or divide, then mark your answer on the number line. Can you get four in a row before your partner?

Discuss and Choose

Stage: 1 and 2 Challenge Level: Challenge Level:1

Discuss and Choose


This activity challenges you to decide on the 'best' number to use in each of the following statements.
 
You may like to talk to someone else about what you're thinking.  You may need to do some estimating, some calculating and some research.
 
Please send us your solutions and don't forget to explain how you arrived at your conclusions.
 
 
 catA
1) There are roughly 10 million/500 million/1000 million domestic cats in the world.
2) On average cats weigh 1.5/4.5/8 kg.
3) Domestic cats sleep on average 8-9/13-14/18-19 hours a day.
 
 DogA
4) There are roughly 400 million/600 million/800 million domestic dogs in the world.
5) The average life of a dog is 10-14/14-18/18-20 years.
 
 
 DolphinA
6) Dolphins live in groups called pods or schools of up to 12/20/30 individuals.
 
 ElephantA
7) Adult elephants need to drink about 100/200/400 litres of water a day.
 
 GiraffeA
8) A giraffe's neck is about 120/170/220 cm long.
9) A giraffe's tail hair is 2/5/10 times as thick as the average human hair.
 
 LionA
10) An average male lion weighs 180/250/330 kg.
11) A lion's roar can be heard 8/12/16  kms away.
12) Lions rest for 10/15/20 hours a day on average.


Why do this problem?

This activity gives an opportunity to discuss the quantities involved in the statements and may involve estimation, calculation and/or research. Children will rely not only on what they have learnt from school but also information they have picked up from elsewhere. The discussion may well reveal some surprises, particularly in terms of their understanding of different units of measurement. 

Possible approach

The activity could be suitable for small group or whole class discussions, depending on the experiences of the children involved.  You might find it helpful to print off copies of this sheet which has all the statements on it.   The statements could be cut up so that each is on a separate card. 
 
The role of the adult in this kind of situation is to enable discussion to take place effectively.  It may be that after an initial discussion about each statement, you assign a pair or small group of children a few statements each and invite them to come up with evidence to support their suggested answer.   If possible, encourage them to record as they go along so that they have a reminder of what they did.

Key questions

So, what do "you" think about what "they" have just said?
Tell us your thoughts about ...
So, what do you all think?
Do some of you agree with ...?
If so, why?  Or why not?
How could we be more sure?

Possible extension

Youngsters could create their own challenges in a similar way for others to discuss.

Possible support

Try to help by listening, sharing and offering thoughts where appropriate.  

The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to embed rich mathematical tasks into everyday classroom practice. More information on many of our other activities can be found here.
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NRICH is part of the family of activities in the Millennium Mathematics Project.