Five squares can require only four moves

Start on the first square of a straight five-square path and count the transitions to the last. The difference between squares visited and moves executed makes a common extra-command error visible.

Moving from square one to square five takes four forward moves.

Count crossed boundaries, not the starting square

Mark start and goal. Count transitions. Test the commands.

Count transitions between adjacent squares rather than the number of squares shown. This makes the source of the extra command visible.

How many boundaries were crossed? Trace with a finger.

Counting the start as a move adds an error.

Resources

• Draw the Robot’s Grid Route – Open-Ended Drawing Worksheet — Use the route drawing as a spatial planning prompt; add your command key separately.

Further reading

• CS Unplugged — Kidbots and algorithm activities
• Australian Curriculum Version 9 — Technologies overview

Read next

• A repeat-until process needs a reachable stop condition
• An event starts an agreed response
• A shorter symbol message must still be recoverable

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