Infinite geometric series worksheet
When the ratio is between -1 and 1 the terms shrink fast enough that the total settles on a number. One formula: the first term over one minus the ratio.
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Sigma Prep · sigmaprep.io/worksheets Name Infinite Geometric SeriesDate Period Find each sum.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
Sigma Prep · sigmaprep.io/worksheets Name Infinite Geometric SeriesAnswer keyVersion 1Date Period Find each sum.
Free math worksheets at sigmaprep.io/worksheets© 2026 Sigma Prep |
How to do these
Find the sum:
- Each term is half the one before, so r is one half.
- The sum is 12 over 1 minus one half.
The answer is .
Where students go wrong
Using the formula when the ratio is bigger than 1. A series like 2, 6, 18 grows without limit and has no sum at all, and the formula will happily give a negative number for it.
Also called sum to infinity or convergent series.