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'Junior Frogs' printed from http://nrich.maths.org/
Why do this problem?
allows pupils to think strategically in an engaging context. They will need to work very systematically, and may also want to develop their own recording system. With very young pupils it helps to re-inforce following rules.
You could introduce this challenge using the interactivity, but it works just as well to have pupils replacing the frogs and toads. The four chosen children can be sat on chairs with the rest of the group offering ideas. Having a go at the initial challenge as a whole class to begin with will help reinforce the rules and may also bring about the need for some sort of recording.
Having got the idea, learners could work in pairs or small groups. At this stage, depending on your focus, you may offer them the interactivity, or some pupils will prefer to have a physical representation in front of them in the manner of small counters, blocks etc. to move around. Keep a watch out for pupils who don't have set places or items representing the lilypads, as it is easy
to lose the empty place!
Emphasise that you are looking out for those pairs/groups who are able to justify their thinking and convince everyone that there really isn't a way of doing it in fewer moves.
Tell me about what you are thinking.
Why that move?
You seem to have some system going on, can you tell me about it?
Some learners will be keen to try larger numbers of frogs and toads. Being able to predict the total number of slides and jumps needed for a given number of frogs/toads is not straightforward but there is still value in encouraging pupils to convince you there is no quicker way to complete the challenge.
Some children may be intrigued by the Towers of Hanoi problem, which is similar in the necessity to work systematically. There are three pegs, and on the first peg is a stack of discs of different sizes, arranged in order of descending size. The object of the game is to move all of the discs to another peg. However, only one disc can be moved at a time, and a disc cannot be placed on
top of a smaller disc. The interactivity in this problem
Some pupils may need reminding of the rules but the interactivity may help in this respect.