The Magic Number and the Hepta-tree
The Magic Number and the Hepta-Tree
The Mathemagician needs to break a dreadful spell! Help him to find the magic number that will do the trick!
Here is the hepta-tree hung with silver balls.
Do you think the balls will have similar values?
Try estimating the amount on each ball.
In order to break the spell, firstly find the exact difference between the largest ball and the smallest ball.
Multiply your result by $244$.
Round this to a whole number and that gives us the MAGIC NUMBER!
Give this number to the Mathemagician and the terrible spell will be broken for ever!
Why do this problem?
This problem gives work on percentages in an interesting and challenging way. It also gives you an opportunity to discuss different ways of estimating and therefore shows learners how expressions which look very different can give very close answers.Possible approach
Key questions
Possible extension
Learners could create more percentages like the ones on the hepta-tree which look different but have very close answers. These could range like the ones in the problem or approximate to another number. It would be interesting to talk to children about how they were coming up with the percentages.Possible support
Using this sheet will help children organise their calculations and it may be appropriate for some to use a calculator.You may also like
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