Based on the name, i'm gonna go ahead and guess 3. Added.
sum
/səm/Submit
noun
1.
a particular amount of money.
"they could not afford such a sum"
synonyms: amount, quantity, volume More
2.
the total amount resulting from the addition of two or more numbers, amounts, or items.
"the sum of two prime numbers"
synonyms: (sum) total, grand total, tally, aggregate, summation
"the sum of two numbers"
