Number and Quantity
Number and Quantity in the LCA Mathematical Applications exam tests your ability to use numbers in practical contexts: wages, bills, VAT, discounts, ratio, proportion, metric units and sensible rounding. Questions often appear as short real-life scenarios rather than abstract arithmetic.
Core rules
- Follow order of operations (brackets, powers, ×/÷, +/−).
- For a percentage increase: new value = old × (1 + rate). For a decrease: old × (1 − rate).
- VAT at 23% means multiply by 1.23; a 15% discount means multiply by 0.85.
- Keep units consistent before calculating; convert cm to m or minutes to hours first.
- Round only at the end, and round money to the nearest cent.
Worked example
A worker earns €12.50 per hour for a 38-hour week. Overtime is paid at 1.5 times the hourly rate. She works 4 overtime hours. Find gross pay. Basic pay = 12.50 × 38 = €475.00. Overtime rate = 12.50 × 1.5 = €18.75. Overtime pay = 18.75 × 4 = €75.00. Gross pay = 475 + 75 = €550.00.
Traps that cost marks
- Applying a discount and VAT to the wrong base, e.g. adding VAT before a discount.
- Treating percentage points as percentages: a rise from 5% to 7% is 2 percentage points, not 2%.
- Rounding hourly rates too early, which changes the final pay.
- Mixing metric units, such as dividing a length in cm by a time in hours without converting.