Sum of cubes of all odd 5-digit numbers

[Brookejewel]

PLEASE HELP! I am so stuck on this, working on it for days

Im trying to find the sum of the cubes of all the odd 5 digit numbers..


if you know a formula that works even with smaller numbers so i can try solving it also but i need the answer as well

 

[micromass]

Hi Brookejewel!

Do you know a formula for all the cubes (up to a certain point). Let's disregard the fact that they have to be odd and have 5 digits.

Do you know a formula for

$$\sum_{i=1}^{1000000}{i^3}$$

for example? Once you know this formula, we will modify it to suit your purposes!