So teachers don't need to be numerate?

There is a piece in this morning's paper about student teachers threatening to take legal action because they won't get their teaching qualification if they can't pass the literacy and numeracy tests.
I don't know what the literacy and numeracy tests involve. I do think all teachers should be able to read, write and do basic arithmetic. After that it should surely be a matter of what it is they are going to teach?  Does a teacher of children who do not yet go to school really need to have advanced algebra and trigonometry? 
I was taught basic research skills twice at university. The first set of  research skills was in the area of psychology. I had to learn "statistics" along with how to obtain samples and much more. In my last year at that university I was given the task, along with another person, of writing a questionnaire that went out to more than a thousand schools. In order to do these things I needed to be both numerate and literate. I was also given the role of writing the questionnaire because my doctoral supervisor struggled to do such things. He was a literate man but he struggled with something like that. 
    "Ask Cat," he would tell his secretary. (It was in the days when senior staff had secretaries.) His secretary would sigh and say, "He needs a letter written about...."
But he would sigh when it came to trying to help me understand statistics. It didn't help that I doubted, and still doubt, their value in what I was doing.
When, some years later, I was doing law we had to do a subject called, "Legal writing and research." It was compulsory. It taught students how to find information and how to cite it. I instantly saw the value in that. It presented no problems to me. When the other first year students were complaining about it I told the English as a second language students I was helping, "It's the most important subject you will ever do."  Law students need to be literate.
But I can also remember having to draw and explain a bell curve to a member of the law school staff. Statistics were completely outside their area of expertise. There had never been any need for them to know about a bell curve until then. I understood and simply accepted that. They knew a great deal more about their area of law than I would ever know. They had the intelligence to get the information they needed when they needed it. 
And I think it may be the same for teachers. They need to be able to read and write and do arithmetic and they need to be able to do those things well enough to get more information if they need it. I don't think a pre-school teacher needs advanced mathematics but they need to be competent at basic arithmetic. They need to be able to read, write and spell.
I suppose the question now is whether they need to be able to do basic coding as well as play the coding games they are supposed to teach. I am not sure it will make them better teachers. It might -
but we might also lose some of the best potential teachers because they are required to know things they don't really need to know.
We would have lost an important piece of research if my doctoral supervisor hadn't helped me with statistics. He would not have written a book if I had not helped to write a questionnaire. 
Surely it is more important to work together on the things that really matter?