I just read that most practical problems (algebraic equations, differential equations) do not have a symbolic solution, but only a numerical one.

Numerical computations, to my understanding, never deal with irrational numbers, but only rational numbers.

Why do mathematicians construct the real numbers and go through the pain of using their complicated properties to develop real analysis, etc. to be able to solve just a few cases symbolically?

Why do non-mathematicians deal with real numbers and symbolic calculation if the majority of cases must use rationals and numerical computation only?

**Answer**

Try to solve x1/3=0 with a “symbolic calculation”. Now try to solve x1/3=0 with Newton’s Method. The point is numerical methods can fail and anyone using numerical methods should have an understanding of mathematics so that they can detect when a numerical method is not working and perhaps even fix the problem. Also as this case shows sometimes the symbolic calculation is easier.

All these computational methods need to be designed and implemented. It takes an understanding of the underlying mathematics to do this.

**Attribution***Source : Link , Question Author : totalnoob , Answer Author : Jonas Meyer*