# Cats and Kittens

Pupils work out how many descendents one female cat could produce in 18 months.

# Practical details

Suitability
National Curriculum levels 5 to 8
Time
45 minutes to 1 hour
Resources
Paper and calculator

# Key Processes involved

Representing
Simplify the problem and choose a method.
Analysing
Use given facts and make informed assumptions.
Interpreting and evaluating
Relate their findings to the problem.
Communicating and reflecting
Present their arguments and reflect on their findings, building towards a credible solution.

# Teacher guidance

Check that pupils fully understand the context. You might use a short (funny, but informed) video on the need to neuter cats http://www.youtube.com/watch?v=CMzW3LIkNLA and ask questions such as:

• The task is about what might happen if you donâ€™t have your cat neutered
• Do you think that 2,000 descendants is a reasonable number in 18 months?
• Use the facts given about cats and kittens to help you decide.

The task requires multiplicative calculations to represent changes over time.

During the work, the following probing questions may be useful

• What are the most important facts, and why?
• What assumptions have you made?
• What did you assume about the average number of female kittens in each litter?
• What does your solution tell you about the statement made in the poster?

More able pupils might question more detailed assumptions, such as:

• How quickly a cat becomes pregnant
• How soon after the start of the 18 months is the first litter born
• Some cats/kittens may die during this period