If we list all the natural numbers below 10 that are multiples of 3 or 5, we get 3,5,6 and 9. The sum of these multiples is 23.Find the sum of all the multiples of 3 or 5 below 1000.

To find the sum of all the multiples of 3 or 5 below 1000, we can follow these steps:

1. Initialize a variable called "sum" to keep track of the running total.
2. Use a loop to iterate through all the natural numbers below 1000.
3. For each number, check if it is divisible by either 3 or 5 using the modulo operator (%).
4. If the number is divisible by either 3 or 5, add it to the "sum" variable.
5. After the loop finishes, the "sum" variable will contain the sum of all the multiples of 3 or 5 below 1000.
6. Print the value of the "sum" variable to get the final result.

Here is an example implementation in Python:

sum = 0

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

print(sum)

The output of this code will be the sum of all the multiples of 3 or 5 below 1000.