Write a multiplication equation and a subtraction equation that both involve fractions

1/2 • 3/4 = 3/8

3/8 - 2/8 = 1/8

multiplication equation = 2/3 x 5 1/3

subtraction equation = 8/9 - 6/9

I would tell Eddie that he is correct if the coin is a fair coin (not weighted to favor one side).  Since coins have two sides, heads and tails, the probability of getting heads is 1 out of 2 or 1/2.  Same for tails (1 out of 2 or 1/2)
Since 325 is half of 650   (325/650 = 1/2) we know that the probability of getting heads in 650 flips is 1/2 or 325

In reality we might expect it not to be exactly 325 heads - could be 321 or 329 or even 338.   But we would not expect 35 heads and 615 tails.