Commas in numbers

So I have an activity where students are supposed to type a function using the number 35,000. When they type the number with the comma, they get a “not correct message” but without the comma, it is correct. I’m not sure if it is my CL. If so, can anyone advise? Here is a link to the screen:

Thank you!

I think using a comma to separate digits is not allowed as commas function as number separators, like when you write an ordered pair (3,2).

I’ve just started adding this message to the instructions,

Do not use commas to separate groups of digits. If you wish to separate digits, use spaces instead, i.e. 10 000, not 10,000.

It’s a decent opportunity to reinforce with students that conventionally you would not include digit separators in a mathematical equation - only the final answer, if applicable.