Someone who translated some mathematics texts for us is using añadir instead of sumar for addition. I am uncomfortable with this, but not fluent enough to say that it is wrong.
Example: "añada a diferencia de fracciones"
for "Adding unlike fractions."
While we are on the subject, "unlike fractions" is being translated both as "diferencia de fracciones" and "fracciones desiguales."
Are there preferred terms here? (We are aiming at both Mexican and Puerto Rican audiences.)