I think the purpose of learning times table is not to recollect it later in the future but to build and train the brain which is necessary. I started taking some lessons in computational chemistry a few days back, and I had to revisit some topics in Advanced Mathematics to be able to grab the programs. This is where finding the value of x comes into play. People built the technology that we are using now because they possessed the required theoretical knowledge. The generation of future technological inventors need the full knowledge of the theory. If one is preparing to be a user, such theories may not be needed.