Problem is:

$\displaystyle (5.0028 x 10^-7) + (6.14 x 10^-10)$

If done on the calculator the result is $\displaystyle 5.00894 x 10^-7 or 5.0090 x 10^-7$

I must be doing something incorrectly...

-Add $\displaystyle 5.0028 + 6.14 = 11.1428$

-Add $\displaystyle 10^-7 + 10^-10 = 10^-17$

So I get $\displaystyle 1.1143 x 10^-16$

Anyone know what I did incorrectly?