A teenage programmer evaluates the instructions she's written to tell her computer how to mop the floor. She checks if they're in the right order, if she's included all the steps, and if her instructions are precise enough. She tests them after each change to see if there is anything she has forgotten. Teacher notes: Units of measurement can be discussed and linked to mathematics, both for measuring the rice (cups) and also for filling the mop bucket (litres). Students could flowchart these algorithms or write them in pseudocode and then peer assess/evaluate them for efficiency.