These two group activities use mathematical reasoning - one is numerical, one geometric.
EWWNP means Exploring Wild and Wonderful Number Patterns Created by Yourself! Investigate what happens if we create number patterns using some simple rules.
Place this "worm" on the 100 square and find the total of the four squares it covers. Keeping its head in the same place, what other totals can you make?
It may be helpful to write out the different combinations of stamps that could be used for each price.