Hi well you didn’t tell me weather your adding them, subtracting, dividing, or multiplying. So here is the answer for all 4 of them. Adding them you get 1261.8, subtracting then you get -43.8, multiplying them you get 397555.2, and dividing them you get 1015/1088. If you just need the answer for each one (5.8x105) is 609 and (6.4x102) is 652.8. Hopefully I helped in some type of way. Have a good night :)