PLEASE HELP! I need both and can’t figure out the answer!

Answer:
a) 11.75 * 10^6
b) 1.35 * 10^-7
Step-by-step explanation:
Here, we want to find the sum and the difference
a) That would be;
(3.48 + 8.27) * 10^6
= 11.75 * 10^6
b) That would be;
(9.58-8.23) * 10^-7 = 1.35 * 10^-7