Rounding down

Another noob question - I want to display elapsed distance as kms completed - kind of like a fixed 1km auto-lap

If I use numofkms.format("%0.0f") it displays correctly with no decimals but does rounding so after 2.5kms it already shows 3.

How do I modify to always round down so that 2.75 still shows 2 until I get to 3.

Can I just use int(numofkms)?