What is the best way to show "up to 20 likes"?

It is common in social networks to show the number of "likes" is some shortened way to save space and not to get into too many details, for example, "3", "60+", "3K", etc.

Recently I read an article, that it makes sense to hide the real number of likes when it is smaller than some predefined amount, so that you don't let underestimate the things that didn't yet received enough attention.

If I still want to display some indicator when there are less than 20 likes, what would be the best way to show that?

• < 20
• 0..20
• up to 20

Are there any de facto standards for that?