Write your answer in scientific notation. (3.2 x 10^-2) + (3.2 x 10^-4) + (2.8 x 10^-2) plz show me the work, thanks

3.2 x 10^-2 + 3.2 x 10^-4 + 2.8 x 10^-2
= 3.2 + 2.8
= 6 x 10^-2 + 3.2 x 10^-4
Convert 3.2 into fraction which is 16/5
And express with a positive exponent using “a^-n = 1/a^n” therefore
= 6 x 10^-2 + 16/5 x 1/10^4
= 6 x 1/10^2 + 16/5 x 10^4
= 6 x 1/100 + 16/5 x 10,000
Reduce 6 and 100 with the GCF ‘2’
Then reduce 16 and 10,000 with 16
= 3 x 1/50 + 1/5 x 625
Multiply
= 3/50 + 1/3125
Then add
The answer is
= 377/6250
= 0.06032

What are the options

The answer is $9.90 with rounding to the nearest tenth