Short finite summations, or partial sums, are common in computer science. For example, one of the most common uses occurs with loop counters. Here is a Python example:

i = 0 while i < 10: i = i + 1 print(i)

The `while`

loop will not stop unless we sum up the value of “i” and test that value. Please note in this particular example, the symbolism in mathematics looks like this:

`$\sum\limits_{i=1}^{10}k$`

where k = 1. Our `while`

loop test value is *nk = 10*. Also, notice that the value “10” at the top of the summation symbol tells us we have a finite summation.

With some problems, the value of *n* may be so gigantic as to be costly to calculate. This condition is often called “uncountably finite.”

### Instructions

**1.**

When you add up the dollars in your wallet, is that a summation?

Set `checkpoint_1`

to `"yes"`

or `"no"`

.

**2.**

Find the partial sum of:

`$\sum\limits_{i=1}^{4}2i$`

Assign your answer to `checkpoint_2`

in the code editor.