620 + 107 round estimate the sum

Okay. 

 620 would be rounded estimate to 600

& 

107 would be rounded estimate to 100 

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?