His wording could be clearer, but going by the principle of charity [1], having a slight grammar issue is more plausible than failing basic high school math. I could be wrong of course, weirder things have happened.<p>[1] <a href="https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Principle_of_charity" rel="nofollow">https:&#x2F;&#x2F;en.wikipedia.org&#x2F;wiki&#x2F;Principle_of_charity</a>