Are you sure about that? You said in your initial post…
What truth are you referring to exactly? That book is too soft science to make that argument. It’s okay though, because elsewhere you said…
…so welcome to the millennia old nature versus nurture debate. 
You should really read up on the topic before making such statements, because you can take the whole thing back another 2,000 years to Aristotle… and then we could argue, “millennia old debate v/s a single book. Not even a question.”
Well, your so-called “blank slate” is really an “erased wax tablet” if you want a better translation of the Latin “tabula rasa” and might also better explain the idea. In fact I just discussed with @thinkaboutthebible the very same image…
…now, I’m not gonna argue that the Ancient Romans/Greeks made a case for neuroplasticity with that analogy but we’re not talking “somethingness from nothingness” here. You should understand the blank slate (the wax tables with Stylo) like a computer with a CPU, ALU ( arithmetic logic unit), etc. that let’s you write a program that you can then execute.
There are various reasons why you could move “counting” into the nature category, as you’ll find some animals able of doing so without really being taught by their environment. Same goes for the “ability to speak” but not language itself.
How about you google “nature versus nurture mathematics” and see where that gets you in terms “the truth” because you’ll find as much research supporting one as you’ll find supporting the other.
Personal opinion is with @Nodas as far as mental math… not the ability to count (that’s just your brain’s ALU)… most likely neither in your DNA from birth nor epigenetics. Anyways, I hope you have some reading material now that let’s you leave a more qualified comment the next time around.