1. A is correct because if you put them all in decimal form.
0.375 (3/8), 0.5 (1/2), 1, 1.414 (√2), 4
2. B is correct because if you get the square root of 8 it's 2.8 roughly.
3. A is correct because 299,800,000 is 2.998 if you move the decimal place to the right 8 times.
4. B is correct because if you follow the scientific notation rules ( has to be below 10, but above 1 ) that leaves to choices, but if the decimal point is right after the 2 it takes 9 places to get there.
5. C is correct because there is more than one apple and cans of soup so they require multiplication to find the sum cost, but the box of cereal is singular so it is only addition.
It's a bit wordy, sorry.