What Does a Period Mean in Math?

Two common mathematical situations require the use of a period (.). The first means a decimal point and the other indicates a precise measurement of time.

The only exception to this is in trigonometry and geometry when equations translate to plotted points on a graph. The distance between these, called the “period,” is also acceptable but not quite the same thing. For general use (and the purposes of this article), the period will almost always refer to a decimal or timestamp.


In math, specifically algebra, a decimal number is an integer that comes in two parts separated by a period. This application is immediately recognizable in money and prices.

The whole number part comes before the period and the fractional part comes after. But this period termed a “decimal point,” shows a value that will be smaller than the whole number before the decimal point.

These numbers represent fractions based on the preceding powers of 10 and read from left to right. The number after the decimal point denotes the fraction in tenths. This is because you can divide the top number of the fraction line by the lower number and it will result in a decimal.

½ = 0.5

5½ = 5.5

¼ = 0.25

10¼ = 10.25

1/10 = 0.10

1/100 = 0.01


The other common use for a period in math is for indicating distance down to specific seconds. This is useful for racing or other pursuits where timing is important. This can involve typing, horses, cars, running, exercising, or a host of other such things.

To indicate time in digit form, there are some elements to understand. When you see a racing time that includes seconds, you’ll see it something like this:


Every preceding number before a colon (:) indicates a larger quantity of time. Therefore, the number above indicates 3 days, 10 hours, 30 minutes, and 26 seconds. If there are no additional colons in the numbers prior to the period, it simply indicates seconds


Hence, this example tells us 30 minutes and 26 seconds. In the event there are no minutes, then you will use a zero (0) before the period:



The use of a period in math is basically for two things: decimal points and time that includes seconds. While trigonometry and geometry incorporate a concept of a “period,” it’s not punctuation.