Hi Margaret!
I agree that the music commas to show beaming in these situations can be omitted in exercises such as these. I’m honestly not sure if it’s a British thing – sometimes in theory books and method books we go a little more towards the “facsimile” presentation, especially if the exercise is teaching something specific such as beaming or the like.
But in a basic exercise, the commas are not required, per the MBC2015.
Hope that helps!