Decimals, fractions and percentages
This page covers the following topics:
Decimal numbers are used to represent a part of a whole number. The decimal point separates the whole number part of a number from its complementary value that is smaller than one. These values that are smaller than one can be interchangeably represented with fractions, decimals, or percentages.
Fractions are a way to represent parts of a whole number or mixed numbers. They are denoted by using a numerator and denominator. To add or subtract fractions, the denominators of the fractions must be made the same by multiplying the numerator and denominator by the same number to create equivalent fractions like, for instance, ²/₈ and ¹/₄. To multiply fractions, find the product of their numerators and of their denominators. And to divide fractions, multiply a fraction with the inverse of the dividing fraction.
A percentage is denoted by the ‘%’ symbol and refers to a part of a whole number in terms of parts per hundred. 17%, for example, means 17 parts out of every 100. A percentage can, therefore, be used to standardise quantities such as, for instance, 20 pencils out of a 200-pencil set which refer to 10% of the set.
A percentage is denoted by the ‘%’ symbol and refers to a part of a whole number in terms of parts per hundred. 17%, for example, means 17 parts out of every 100. If a percentage of a quantity is known, then the original quantity can be calculated with the use of the formula:
Appreciation occurs when the value of a good increases and depreciation occurs when the value of a good decreases. Appreciation and depreciation are usually quoted in percentages of an original amount and are given as an annual rate of change such as, for example, a 4% depreciation in the value of a car with every year. Appreciation and depreciation may also compound over a length of time which means that when interest is paid on an amount, the added amount then also receives interest from then on.
Fraction, decimals, and percentages are interchangeable ways to represent parts of a whole number and each of the three can either be a positive value or a negative value. These quantities can, therefore, be compared and ordered by using the symbols provided.
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