Consumer Mathematics: Financial Management · Form 4
What is value per unit?
Value per unit is the price of one single unit, found by dividing the total price by the quantity, and it lets you compare items sold in different pack sizes on equal terms.
Price for one unit
Value per unit, often called unit price, is what a single unit costs: one gram, one millilitre, one piece. You get it by dividing the total price by how many units are in the pack, for example RM6 for 500 g is RM0.012 per gram.
Because every option is then expressed in the same 'per one unit' terms, packs of different sizes can be lined up directly. It turns 'RM6 for this, RM10 for that' into a single figure you can compare.
Why it lets you compare
Shops sell the same thing in many pack sizes, so the sticker price alone tells you little about which is better value. Reducing each to a price per unit removes the effect of size and leaves only the rate you are paying, which is the thing worth comparing.
In consumer-maths 'best buy' questions this per-unit figure is the bridge between two prices that are otherwise not comparable, the smallest value per unit is the best buy.
The bigger-pack myth
A question is asking for value per unit whenever it gives prices for different quantities and asks which is better value or the 'best buy'. The usual misconception is that the biggest pack is always cheapest per unit, often it is, but not always, which is exactly why the question makes you check.
Watch the units too: to divide fairly, both quantities must be in the same unit, so 1.5 kg and 800 g need converting to the same measure before the per-unit prices mean anything.
Source:DSKP KSSM Mathematics Form 4 and 5 (Versi English)
Frequently asked questions
How exactly do I calculate value per unit, and what does it tell me?
Divide the total price by the total quantity, giving price per single unit (e.g., per gram, per litre, per item). A lower value per unit means that item is cheaper for the same amount, letting you compare products sold in different pack sizes fairly.
Why can't I just compare the total prices of two different pack sizes directly?
Because a bigger pack naturally costs more in total even if it's actually the better deal per unit. Comparing totals without dividing by quantity can make the worse-value option look cheaper, so value per unit is needed to compare fairly.
What mistake do students commonly make when the quantities are in different units?
Forgetting to convert both quantities to the same unit (e.g., grams to kilograms) before dividing. Comparing 500 g at one price with 2 kg at another price without converting first gives a meaningless, wrong comparison.