Find the sum of the following measurements: reported correctly. 5.1 x 105 m + 5.22 x 105 m

Convert 0.000123 into scientific notation with the same number of sig figs. (Your answer should be in the format M x 10N U) (M is everything on the left. N is your exponent including a negative sign (if applicable) in front with no space between negative sign and exponent's number) (Examples: 2.5678 x 10-2 m, 2.5 x 105 m2) (you would type m2 for m2)