.NB file extension

This is the basic program to work with .NB extension

Wolfram Mathematica

Wolfram Mathematica Mathematica Notebook

For three decades, Mathematica has defined the state of the art in technical computing—and provided the principal computation environment for millions of innovators, educators, students, and others around the world. Widely admired for both its technical prowess and elegant ease of use, Mathematica provides a single integrated... (more)

The program works with the following extensions: m, ma, nb and nbp

.NB extension is also supported by the following programs:

Wolfram Mathematica Player

Wolfram Mathematica Player Mathematica Player Notebook

Mathematica is renowned as the world's ultimate application for computations.
Wolfram Mathematica for Students

Wolfram Mathematica for Students Mathematica Notebook

Mathematica is ideal for students enrolled in a variety of courses.