When I wanted to learn how to drive a car, my father didn't require me to first put the key in the ignition 50 times, then turn the lights on and off 150 times, push the brake and gas pedals 500 times each, adjust the rear view mirror 120 times for daylight and 120 times for night, etc. before he thought I was ready to drive. Instead, my father took me out in the high school parking lot and, after a brief talk, had me begin to drive around it. White knuckles and all, he was the guide on the side not the sage on the stage. He put me in a situation where I had a need to learn how the pedals and knobs worked and where I had to get them to work together in a sort of performance assesment. Of course I didn't drive well at first but I soon got better at it and learned how to use all the pedals and knobs though experience and in a meaningful context. I still don't know how every part of the inside of a car works exactly but I do know, through experience, how the driving part works in the sense that, for example, I'm able to easily merge onto the expressway from a dead stop in rush hour without having anyone slam on their brakes (well on most days, anyway).
I was never told that I couldn't drive until and unless I first mastered the set of all of the pedals and knobs in front of me. Same deal when I started to work with computers. But that is what we did with mathematics instruction in the past. We broke it down into someone's idea of sequential sets of specific skills that must all be mastered before moving on. No wonder mathematics doesn't make sense and can't be used in new situations by so many people today.
If I was required to do all that before I could even begin to drive, I'd most likely still be taking the bus (or rather, still trying to pass the 100 question, timed, multiple choice test to allow me to move on to actually waiting at the bus stop).
If we want kids to be able to think mathematically and to use mathematics to help them make sense of things and solve problems, we need to give them experiences where they have to do just that.