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Harriet tried this problem out:
My hand's not as big as my mum's, so it took more spans to go round the tree. So if I told you how big the tree was, you might think that it was bigger than if my mum told you. So it's better to use a tape measure and use centimetres or something because then we'll all give the same answer.
Hand Span
Age 5 to 7
Challenge Level 
Harriet tried this problem out:
My hand's not as big as my mum's, so it took more spans to go round the tree. So if I told you how big the tree was, you might think that it was bigger than if my mum told you. So it's better to use a tape measure and use centimetres or something because then we'll all give the same answer.
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