Simple inline math . $1+1 = 2$ .

1+1=21+1 = 2

. Simple block math . $$1+1 = 2$$ .

1+1=21+1 = 2

. Ignore single dollar sign . It costs $5. .

It costs $5.

. Ignore multiple dollar signs in separate paragraphs . This costs $5. That costs $10. .

This costs $5.

That costs $10.

. Inline math inside heading . # The $N$-eigenvalue problem and two applications .

The NN-eigenvalue problem and two applications

.