There are 300,000 species of angiosperms on earth and 840 species of gymnosperms. what percentage of seed plants are angiosperms ?

First, we're going to add the species of angiosperms and gymnosperms together.
300,000 + 840 = 300,840

Then we're going to multiply 300,840 by 300,000.
300,840 x 300,000 = 9.0252E10

We're going to round the hundredth to the tenth now.
9.0252E10 = 9.0

This is how we know 9% is angiosperms and 91% is gymnosperms.

Your answer to this question is 91%.

Hope this helps!~