Typesetting Math Without Computers Was a Whole Thing
Typesetting mathematics without a computer was a whole different thing. Even after hot metal was the norm, math often required hand composition to insert any characters that weren’t the same point size as the body text.
In this image, the metal spacers have been pushed up so they print as well.
From The Printing of Mathematics by T. W. Chaundy, P. R. Barrett, and Charles Batey, 1954.