Sumar se usa casi sólo cuando se refiere a números. Si se está haciendo una mezcla de ingredientes de cualquier tipo se usa añadir o agregar, por lo general de esta manera se traduce el verbo add.
Sometimes the pronominal verb sumarse is used like unirse.
I join that cause - Me sumo a esa causa / Join! - ¡Únete!
I add (añadir) a cup of water to the recipe. I add up (sumar) the numbers.
Sumar has the same root as "sum".
I'd say " sums up" rather than just "sums", but either way DL doesn't like essentially colloquial English.
This is also how I use 'sum' v. 'sum up' as a native English speaker. I do not think this usage is colloquial, though it may not be officially recognized.
I think that "He adds up the numbers" would be a better translation than "He adds the numbers".
How about "He crunches the numbers" for extra credit in renagade creativity?
This would not be preferred, at least where I live, but it is still a valid one-to-one translation.
Isn't adding up the same as adding so why cant i put he adds the numbers up
I wrote 'He sums the numbers'... Is that just bad English or could it be an alternative, here? Thanks for your time!