Case Math Practice
Eight short, fictional arithmetic drills for the kind of quick back-of-the-envelope math that comes up in case-style interviews. Every number is fictional, every value is fixed, and calculations run in your browser; submitted answers are not sent to the site. No login is required. Submitted answers and progress are not saved, and the tool does not score or evaluate your response.
How to use
- Read the prompt at the top of the exercise card.
- Enter digits and an optional decimal point. For negative cash headroom, use the minus-sign button beside the field; do not enter commas, currency signs, or unit labels.
- Tap "Show working" to see the formula, the step-by-step calculation, and the final result for the current exercise.
- Use "Next" to move to a new exercise, "Previous" to revisit one you have already seen, or "Shuffle" to jump to a random exercise from the eight. There is no scoring, no history, and no saved progress.
Monthly break-even units
A product has a monthly fixed cost of NT$250,000, a unit price of NT$950 per unit, and a variable cost of NT$600 per unit. How many units per month must be sold to break even?
- Monthly fixed cost
- NT$250,000
- Unit price
- NT$950 per unit
- Variable cost per unit
- NT$600 per unit
- Contribution per unit
- NT$350 per unit
Formula
Monthly fixed cost ÷ (unit price − variable cost per unit) = break-even units per month. Apply ceiling once, at the final step, because the result must be a whole number of units.
Working
NT$250,000 ÷ (NT$950 − NT$600) = NT$250,000 ÷ NT$350 per unit = 714.285714… units per month before rounding. Round up only at the final step: 715 units per month.
715 units per month (answer rounds up only at the final step).
What this result does and does not say
This calculation alone does not make an investment or business recommendation. It assumes the supplied fixed cost, unit price, and variable cost, and it answers only the arithmetic question of how many units cover the supplied fixed cost at the supplied contribution.
Exercise 1 of 8
Monthly break-even units
A product has a monthly fixed cost of NT$120,000, a unit price of NT$800 per unit, and a variable cost of NT$500 per unit. How many units per month must be sold to break even?
- Monthly fixed cost
- NT$120,000
- Unit price
- NT$800 per unit
- Variable cost per unit
- NT$500 per unit
- Contribution per unit
- NT$300 per unit
Eight fixed fictional practice scenarios. Amounts are in NT$.
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