Amazing but a tiny issue

So,it is just like the pictures above. But when you get a question wrong it doesnt give you an explanation for why it is wrong. I would like an explanation.

Hint : the one where it asks you to add numbers like 1000 and 20 something the answer is 4110.

Some dont make sense. It is very confusing but I love it. Besides that one issue.

Liv s lunch about Stupid Test!, v3.3