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## 'Big and Small Numbers in the Living World' printed from http://nrich.maths.org/

### Why do
this problem ?

Practice with the use of numbers is a crucial biological skill.
These interesting

questions will allow you to practice these skills whilst
developing awareness of orders of magnitude in scientific
contexts.

### Possible approach

There are several parts to this question. The individual pieces
could be used as starters or filler activities for students who
finish classwork early. Enthusiastic students might work through
them in their own time. Since there is no absolutely 'correct'
answer to many of these questions, they might productively be used
for discussion: students create their own answers and then explain
them to the rest of the class. Does the class agree? Disagree? Is
there an obvious best 'collective' answer?

### Key questions

- What assumptions will you need to make in this question?

- How accurate do you think you answer is?

- What order of magnitude checks could you make to test that your
answer is sensible?

### Possible extension

Can students make up similar questions? Can they put any upper or
lower bounds on the numbers?

### Possible support

Students might struggle with the 'open' nature of the questions. To
begin, they might like to read the

Student Guide to Getting Started with rich tasks