'Plausible Estimation' Estimating for
Amazing Facts Tasks - Set #3
Malcolm Swan
Mathematics Education
University of Nottingham
Malcolm.Swan@nottingham.ac.uk
Jim Ridgway
School of Education
University of Durham
Jim.Ridgway@durham.ac.uk
The aim of this assessment is to provide the opportunity for you to:
· develop a chain of reasoning that will enable you to estimate quantities to an appropriate
degree of accuracy
· choose suitable units for your estimate
· communicate the assumptions upon which your estimate is based.
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1. High stack
Suppose you have a very large sheet of paper. You tear it in half and put one half on top of the
other. You now have a stack of two sheets.
You now tear the whole stack in half and place one half on top of the other to make a new stack.
You repeat this process, tearing 50 times. (Yes I know its impossible - just imagine you could).
How high would the stack be? 50 feet? 100 feet? A mile? or more...? Make a sensible estimate,
based on careful reasoning.
Assumptions
Reasoning
2. The swimming pool and the glass.
How long would it take you to empty an olympic size swimming pool with a glass?
Assumptions
Reasoning
3. The briefcase of cents
Suppose you filled a briefcase with one cent coins.
How much would the money be worth?
Assumptions
Reasoning