After a year of successful gardening using his magic doubling shed
(introduced in Magic Potting Sheds), Mr McGregor buys a new shed
that trebles the number of plants in it each night. Use the
interactivity to investigate how many plants he needs this time to
get the same number in each garden. What is the smallest number of
plants he could use?
Can you predict how many plants he would need on the first day and
how many he should plant each day if he bought a new shed that
quadruples the number of plants in it each night?
Use the interactivity to test your prediction.
Mr McGregor is so successful that he decides to plant more gardens.
He can still only plant one garden each day.
Use the interactivity to change the number of gardens and
investigate how many plants he should use for each of the different
What do you find?
Can you find a general rule?
Can you explain why your rule works?
Unfortunately, Mr McGregor suffers an attack from evil magic slugs
that eat half of the plants in his (non-magic) potting shed each
night. He still wishes to plant the same number of plants in each
How many plants does he need on the first day this time, and how
many should he plant each day? (Remember that he can only plant
whole numbers of plants!) Use this interactivity to help you.
The NRICH Project aims to enrich the mathematical experiences of all learners. To support this aim, members of the
NRICH team work in a wide range of capacities, including providing professional development for teachers wishing to
embed rich mathematical tasks into everyday classroom practice.