At age 5, how much would you have to save per month to have $1 million in your account at age 65, if your investment rate was 10% per year? Assume no taxes and compounding on a monthly basis.

$213.30
$21.23
$274.60
can't be done with these assumptions.

Using http://www.math.com/students/calculators/source/compound.htm

21.23 a month seems to pretty close. Remember that the contributions continue during the 60 year period.