Can I use 20" mountain bike tyres on my folding bicycle?

I have a 20inch folding bike with the diameter of the tyres just under 2 cm. The back tyre was worn out nearly running on just the inner tube and when I went over a rock today it just blew. As I like going offroad, can I get a 20inch mountain bike tyre for replacement?(ie, the type seen on mountain bikes for kids?) Thanks.
oh god, sorry, i meant 2 inches for the tyres diameters.

Probably not, you need to check the ETRTO size for your tyre and buy a new one with the same designation, and as 2cm. is very narrow for the width, I suspect that your tyre is 20" x 1 3/8", or ETRTO 37-438, this will not accept a MTB tyre.
All these sizes should be on the side wall of your ex tyre, if in doubt, take your bike to your local bike shop, they will sort you out, and also advise if you can fit a wider tyre.
Yes, so long as the tyres aren’t too wide and they don’t foul against the frame (ask at the shop, preferably it should be the exact same width) you can fit off-road tyres.