Examples of unsolved maths theorems...

• The Syracuse problem or Collatz problem

This problem was been posed by L.Collatz in 1937 and it's still unresolved. It consists to take an number which positive and integer. Then you have to devided this number by two if it's an even number. Overwise, if it's an odd number you multiply by three and you add one. And you repet these steps until obtain one. We know that with this problem all numbers until 19.2^58 give finally one. But actually nobody have found a demonstration to proove why all the integers numbers give always are at the end.