quick math tricks

number fun

# 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.


# first lets grab everything from 1 -> 1000 that has no remainder if i / by 3 or 5
$num_to_sum = @()
1 .. 1000 | foreach {
  if (($_ % 3 -eq 0) -or ($_ % 5 -eq 0)) {$num_to_sum += $_}
}

#So Measure object can do the sum work, but it likes to output multiple attribs 
#we dont care about, so a quick filter.
($num_to_sum | Measure-Object -Sum).Sum