Moving past sequences, we now look at summations. A summation, as the name implies, is the addition of a sequence of numbers.

As discussed earlier, sequences are ordered. Summations, which add up the terms of a sequence are also ordered; however, they use a special notation to create a shorthand description. Example:


Where i = 1 is the initial value, n is the terminal or “stop” value, and i by itself is the description of a single element of the sequence we will sum. Suppose the value given for n is not a number, but infinity, in that case we see an infinite series. Sometimes an infinite series will converge to a target value, such as the example of the natural root e we saw earlier. Note that we are not always this fortunate with summations, in many cases an infinite series summation will be infinity.



Does the “stop” value in a summation have to be finite?

Set checkpoint_1 to "yes" or "no".


Can the initial value be negative?

Set checkpoint_2 to "yes" or "no".

Take this course for free

Mini Info Outline Icon
By signing up for Codecademy, you agree to Codecademy's Terms of Service & Privacy Policy.

Or sign up using:

Already have an account?