School solver---a good math platform

School solver is a good platform, which can help retired teachers to earn money and devote mathematics skills to students, my many friends like this platform, but when they registered, they are required to take some examinations, they like to do the tests, but when they are asked to pay money to take examinations, they cannot understand, you know, it is a little hard for them to add money into the account in China, and they think it is not 100% reasonable. Oh, I agree with them, in fact, although I like the School Slover, when I know that somebody must pay to attend such tests, I don’t think it is a good way.

Why School solver charge tutoor’s money to take tests ? does the School solver earn money by testing? I cannot understand. Actually many experienced math teachers have skills, but it is hard for them to pass such boring test.  Sometimes math language is different so called Standard English language, who knows math language should know English language.