find the sum of all multiples of 3 between 1 and 1000 code example

Example 1: Sum of all the multiples of 3 or 5

const findSum = n => {
  let countArr = []
  
  for(let i = 0; i <= n; i++) if(i % 3 === 0 || i % 5 === 0) countArr.push(i) 
  return countArr.reduce((acc , curr) => acc + curr)
}
console.log(findSum(5))

Example 2: find the sum of all the multiples of 3 or 5 below 1000 python

nums = [3, 5]

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

print(result)