I'm having some trouble converting square/cubic metric units.

Ex:
1500 cu. cm = ? cu. dm?

I have this number line thing that helps, and so far I know that you divide by 10 (I think, decimeter is higher than centimeter, yes?), but now what?

Thank you!

Start with the relation beween cm and dm.

1 dm = 10 cm

Now figure out the relationship between CUBIC dm and CUBIC cm.

1 cubic dm = 1 dm * 1 dm * 1 dm
1 dm * 1 dm * 1 dm = 10cm * 10cm * 10cm

so

1 cubic dm = 1000 cubic cm

See if you can take it from there.