I remember when we got our first calculator in 1974, I thought, “hey man, this would be good for math class!” I was in second grade at the time. My maternal grandmother said, “if you use that all the time, your brain will rot.” I am still in contact with one of my former high school teachers and he says that calculators are OK, but you should know the theory to do it by brain and hand first. I think those are good things to think about and remember. The calculator is there to save time but I think one needs to know the math theory first.
I taught my children Saxon Math through 8th grade with no calculators, then a quick calculator course to get them up to speed for HS math.