*Source code available on GitHub.*

This first problem gets us off to an easy start. It asks:

We want to iterate through all the numbers below 1000, so we’ll use a `for`

loop:

for i in range(1,1000):

This tells Python to start with `i=1`

and keep incrementing `i`

every loop up until `i=999`

. The easiest way to check for divisibility is with the modulus operator, `%`

. Writing `x % y`

returns the value of – that is, the remainder when dividing by .

So, using an `if`

statement, we write

if i % 3 == 0 or i % 5 == 0:

which will return true when the number is a multiple of (had zero remainder when divided by) either 3 or 5. If this happens, we want to add `i`

to some sum so that when the `for`

loop terminates, that value is our final value. We’ll call it `running_sum`

.

Lastly, we want to print the result. Here’s the final code:

running_sum = 0 for i in range(1,1000): if i % 3 == 0 or i % 5 == 0: running_sum += i print(running_sum)