Consumer Mathematics: Financial Management · Form 4
What makes a fair money comparison?
A comparison of two money choices is only fair when they are lined up on the same basis, the same time period, the same quantity, and every cost included, so you are comparing like with like.
Comparing like with like
When two options are set side by side, the numbers only mean something if they measure the same thing. That means the same period (monthly against monthly, not monthly against yearly), the same amount or size, and the same set of costs.
If one price includes delivery and the other does not, or one is for 500 g and the other for 1 kg, the raw figures cannot be compared until you put them on a common footing.
Why the basis matters
A cheaper-looking price can easily be the dearer choice once everything is on the same basis, a lower monthly figure over a longer period may add up to more in total. In consumer-maths questions the whole task is often to convert both options to a shared measure, such as cost per month or cost per unit, and then decide.
The comparison, not the headline number, is what answers the question.
Spotting an unfair comparison
Before comparing, check three things line up: the time period, the quantity, and what is counted in the price. If any of them differ, the comparison is unfair until you adjust it, that adjustment is usually the real work of the question.
The common mistake is to pick the smaller number straight away; a monthly payment can look small only because it runs for more months. Match the basis first, then compare.
Source:DSKP KSSM Mathematics Form 4 and 5 (Versi English)
Frequently asked questions
What does it mean to compare two money choices "on the same basis"?
It means lining up both options over the same time period, the same quantity of goods or money, and including every relevant cost, not just the sticker price. For example, comparing a loan's total repayment, not just its monthly instalment, against another loan's total.
Why do exam questions insist on converting to the same unit before comparing?
Because prices, rates or periods given in different units (per kg vs per pack, monthly vs yearly rate) cannot be judged directly, you must convert them to a common unit first, otherwise the "cheaper" or "better" option you pick may actually be wrong.
What's a common pitfall when a question asks which choice is "more worthwhile"?
Focusing on only one figure, like price alone, while ignoring quantity, quality, or added costs mentioned in the question. Marks are usually given for showing the full converted comparison, not just stating an answer.