Is there a format for displaying numbers rounded to the nearest 10, and
numbers in the 1000s (upto 9999) to the nearest 100?

For example display 874 as 870 and display 8765 as 8 800.

I know about commas and "000" for thousands and millions (eg using ###,
"000" to format 123456 as 123 000).

But I've been unable to discover any information for doing something similar
to tens and hundreds.

cheers,
Christopher