How can logical values be added & multiplied?

[dindigul]

Hello
In one of the tips on this site, it goes something like this:
=SUMPRODUCT($B2:$B5<C3)*($B2:$B5>=C2)
though it works, what I don't understand is that when input as single equations =($B2:$B5<C3) and =($B2:$B5>=C2) both evaluate as True and False, but when combined like above, do produce some results like 1, 2 0 etc. Could anyone explain what is happening?
Thanks

[VBA Noob]

This link should help explain

http://www.xldynamic.com/source/xld.SUMPRODUCT.html

VBA Noob