Some and sum are easily confused words.
The spell-check application of most word processing software programs would not catch a slip-up of these two words. Spell-check is looking for words that aren’t in its dictionary, and words that resemble words in its dictionary but are possibly spelled wrong. Spell-check isn’t perfect. It doesn’t know and can’t guess what word you wanted or what word you meant, it can only judge the words on the page. If you used words that are all spelled correctly, it gives you a pass anyway.
Autocorrect suggests words that start with the same letters. It’s suggesting what word you may want to save time, but quite often, its suggestions are pretty off base. They don’t help you out, but they do make you laugh.
Some has multiple forms that all revolve around an ambiguous quantity.
- As a pronoun, it means a group, usually people, of an unknown, but significant number: i.e., Some feel fried chicken isn’t healthy.
- As an adjective, it modifies a noun: some days, some people, some cats. Again your talking about a group of things, but you are identifying those things.
- As an adverb, it modifies a number or another approximation.
Sum also has multiple forms.
- As a noun, it means the answer of an addition problem.
- As a noun, it means the total of the components or parts of something.
- As a verb, it means to do the math, to survey, to determine the results.
The following story uses both words correctly:
Sommersby was finding it difficult to sum up how he felt about his latest breakup; he had thought Simone was the one, and now it was over. It was going to take some time.