# Clubsuit gives Missing $inserted error I am trying to tag an equation with a card suit. My equation works fine with other labels but the suits do not work. $$y^2 + 2 = x^3, x, y \in \mathbb{Z}. \tag{\kreuz}$$  This works, but, $$\lvert x^2 - 2y^2 \rvert = 1 \tag{\clubsuit}$$  Gives error: Missing$ inserted

Any ideas?

-
Welcome to TeX.SX!. Can you please add a full minimal working example so that people can see what packages etc you need to get your code to work (but don't add code that is not needed). This makes it much easier for people to help you. – Andrew Aug 18 '14 at 6:49

Content inside \tag is not in math mode! (I am surprised too). As \clubsuit is to be used in math mode, add \$ around \clubsuit.
\documentclass{article}
$$\lvert x^2 - 2y^2 \rvert = 1 \tag{\clubsuit}$$