You have twelve weights, one of which is heavier or lighter than the rest, but you don't know which one is heavier or lighter. Using just 3 weighings on the balance, can you identify which weight is the odd one out, and whether it is heavier or lighter?
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.