I was thinking the same thing while watching. My guess- It is a verbal problem with appropriate pauses and not written down. I'm sure that they went over it all beforehand and explained how it was to be done and answered any questions the kids had; probably a few rehearsals.
Verbal pauses or not, someone hearing impaired or someone who knows anything about math, would see that what's listed on the screen is incorrect. Parentheses are the only pause known in the math world.