A number of objects arranged in a definable order.
In math, a series is what we get when we add the terms of a sequence together. While a sequence lists numbers in order, a series combines them through addition.
For example:
If the sequence is 2, 4, 6, 8, the series is:
2 + 4 + 6 + 8 = 20
There are different types of series depending on how the numbers behave, such as:
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Arithmetic series – where each number increases by the same amount (like 2, 4, 6…)
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Geometric series – where each number is multiplied by the same factor (like 2, 4, 8…)
Series help us explore patterns, sums, and more complex mathematical ideas, and they appear in everything from computer science to finance.
When Do Students Learn About Series?
Students first work with sequences, then build on that knowledge to understand series and how to calculate their totals.
Grades 6–8 – Introduction to Sequences and Simple Series
Students explore number patterns and begin writing and summing simple series.
Grades 9+ – Working with Series in Algebra and Pre-Calculus
Students study arithmetic and geometric series, learn to calculate sums using formulas, and apply series in more advanced problems.
