- problem of the 13 spheres
- problem of the 15 schoolgirls
- problem of the 36 officers
- problem of the advance of Mercury’s perihelion
- problem of the kings
- problem of the needle
- problem of the queens
- problem of the seven bridges of Konigsberg
- problem of three bodies
- problem of touring the world
- problem of trisection of an angle
- problem of two bodies
- problem on knight’s moves
- problem on lattice points
- problem-oriented history
- problem-oriented language
- problem oriented policing
- problem regions
- problem representation
- Problems of Dostoevsy’s Poetics
- problem solving
- problem space
- problem space model
- problem teaching
- problem tracking