As you know, before symbolic notations were introduced and adopted by the mathematical community, even simple statements were written in a very complicated manner because the writer had (nearly) only words to describe an equation or a result.
What is an example of a very simple math statement in old literature which is, verbatim, a pain to understand?
Here’s Proposition 2 from Book 5 of Euclid’s Elements:
If a first magnitude and a third are equal multiples of a second and a fourth, and a fifth and a sixth are equal multiples of the second and fourth, then the first magnitude and fifth, being added together, and the third and the sixth, being added together, will also be equal multiples of the second and the fourth, respectively.
Or in modern notation: a(x+y)=ax+ay.