Engineering is more than math. Engineering is like problem solving which requires persistence, positive attitude to problem solving, ability to learn new techniques and ability to apply the theory to the real-world problems. A good engineer is a good problem solver with positive attitude who tries to find good/optimal/practical solution for the problems, which requires persistence, theoretical understanding of the basics, ability to learn new techniques, and ability to apply that knowledge to real-world problems. Math is problem solving, which requires persistence and positive attitude for problem solving, and ability to apply the learnt techniques to given problems.
Engineering, like so many other things in the life is a combination of ability and attitude. With a good attitude you can accomplish a lot. With a bad attitude, you will accomplish very little. You do not have to be an expert on everything, but you need to have a will to learn new things, to be able to communicate with the clients and fellow engineers, to be able to grasp the concepts from the experts which typically requires at least some theoretical knowledge, and to be able apply the concepts successfully to your work. It is all about attitude. Like problem solving and math.