Always use PEMDAS as order of operations:
parentheses before exponents before multiplication before division before addition before subtraction = P.E.M.D.A.S.
Since we have only addition, subtraction, multiplication, and division, we need to do:
M>D>A>S
5 + 5 - 2 * 7 / 8 + 98 - 64
5 + 5 + [-2 * 7] / 8 + 98 - 64. first
5 + 5 + [-14 / 8] + 98 - 64. second
(10) + [-1.75 + 98] - 64. third
[10 + 96.25] - 64. fourth
106.25 - 64. last
42.25
????
