Let´s define series,
A series has a sequence of partial sums, if the sequence of the partial sums converges that means that,when the limits approaches to any numeror L; in this case the value of series is also L. If the sequence of partial sums diverges, then the infite series also diverges.
Here is an example of Converget series.
Suppose that you take a loan to pay your new Porche, monthly the interest will be low. If you make payments per month of a good amount in a determined moment your loan balance will be zero. As we can see here we are able to know the quatity of months that the person has to pay for the loan, so will be a specific number and as we know if the sequences of this payments have an orden and a pattern that approaches to any number will converge, as well as the partial sums of the series .
Another example is if we eat a pear, first the half, after the half of the half, then the half of the half of the half, etc. we know that this sequences has a logical order and converge to one fished pear; the partial sum of this series will also converge to one pear.
Here is an example of Divergent series.
An interesting example of divergent series is a sunflower, because we find that has several spirals or patterns that are different so we do not have a defined limit, it means that the sequences diverges, this implies that the partial sum will also be infinite so that the series diverges.