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The Deca Tree

Age 7 to 11
Challenge Level

Thank you to everybody who sent in their solutions to this problem. We had lots of detailed explanations sent in.

Pei Lin from Scotholme Primary School in England found the total number of leaves and then subtracted each number separately:

Thank you for showing us how you worked this out. James from Hamstel Junior School in England found the solution by working out how much to subtract in one go:

The woodcutter removes:

1 trunk = 1000 leaves

1 branch = 100 leaves

1 twig = 10 leaves

1 leaf = 1 leaf

This means the woodcutter removes 1,111 leaves in total.

Well done, James!

We had lots of other solutions sent in that were very similar to either Pei Lin's solution or James' solution. Thank you to the following children for their clear explanations: Sandra from Belgium; Dylan from the UK; Humphrey from Twyford School in England; Anna, Serenade, Akira, Maddox and Kenny from Sahuaro Elementary in the USA; K from Crossflatts Primary School in the UK; Elliot from Haddington Primary School in the UK; Penny from Hillbrook Primary School in the UK; Isla Eve from Walton and Holymoorside Primary School in the UK; and Parker from JPSS in Australia.

James also used the phrase 'power of 4' to describe multiplying ten by itself four times:

The total number of leaves on the complete Deca Tree is 10 to the power of 4 which equals 10,000 leaves.

This is a quick way of working out the number of leaves on the original tree - well done!