grid moves

the purpose of these tasks is to involve students in simplifying expressions
although the letters are not used as variables, it is also a simple introduction to vectors
and an application of 'pythagoras' to find (direct, crow flies) journey lengths

can be used to ask about journeys, e.g. from R to D
from D to R etc.

consider why the journey stages sum to 0

could involve 'pythagoras' in working out the lengths

thanks to onlinedungeonmaster for this graphic

questions (9) and (10) contribute to an understanding of solving simultaneous equations