Need some help on coming up with random number from 2 excel columns.

Hi, I need some help in coming up with some random numbers from 2 columns in an excel file.
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If you see on the attached file on column F and G there are some numbers. I need to come up with some random numbers and put them in column H. But the number from column F needs to be a few numbers higher (sometimes a number up, or 2 numbers up, up to three numbers up, but they need to be random throughout the whole column, (like I said sometimes 1 or 2 or 3 numbers up). On column G is the same but the numbers need to go down by 1 or 2 or 3 numbers, just random numbers. On the results on the H column the left number needs to be smaller than the right number. If you see on the attached file the first result in column H .428 is lower than .440 (The number on the left needs to smaller. I'm really trying to come out with a formula but I cant figure it out. Its a long list maybe someone can help me on this if is even possible.

Thanks in advanced