Which offer really costs less?
Packs come in different sizes. Compare like with like.
The same fruit comes in three packs: A, 2 kg for €3; B, 750 g for €1.20; C, 600 g for €0.90. Choose ALL packs tied for the lowest price per kilogram. There are no other costs.
What you will practise: Convert to the same units before comparing.
Think it through together
One person proposes a strategy; the other asks “why?” and looks for a case where it fails. Then swap roles. No names or speed competition needed.
Before viewing the explanation: what do we know, what are we assuming, and how would we check the result?