To work out how many times greater something is compared to another, we have to divide the larger number by the smaller
To put it more simply, imagine you had 30 apples and I had 6. To work out how many times greater your apple collection was than mine, you would divide your 30 by my 6, and find that you had 5 times as many apples as me (30 ÷ 6 = 5).
The principle is the same here, how many more viruses (3 x 10⁹) are there compared to protozoa (5 x 10⁵)?
