Use units to catch a wrong answer

For [WORD PROBLEM] and [LEARNER LEVEL], solve with quantities and units at every step. Then show two plausible wrong solutions: one with a unit mismatch and one with a sensible unit but wrong magnitude. Give a learner checklist for catching both, an independent practice problem, and its worked key. Do not silently assume a conversion factor; state and verify each one. Check arithmetic, final units, and whether the practice problem can be solved from supplied information.