Microsoft Math is a Home & Education software developed by Microsoft Corporation. After our trial and test, the software is proved to be official, secure and free. Here is the official description for Microsoft Math:

Edit by Marydown: Get help with math and science homework
With Microsoft Math, students can learn to solve equations step-by-step, while gaining a better understanding of fundamental concepts in pre-algebra, algebra, trigonometry, physics, chemistry and Calculus.

Microsoft Math provides a set of mathematical tools that helps students get school work done quickly and easily. With a full-featured Graphing Calculator that’s designed to work just like a handheld calculator, Microsoft Math offers a wide range of additional tools to help students with complex mathematics.

From basic math to precalculus, Microsoft Math helps you visualize and see mathematical concepts as you’ve never seen them before. It gives you step-by-step instruction, while providing you with a better understanding of fundamental concepts.
Microsoft Math includes:

Step-by-step instruction to help solve difficult math problems with the Step-by-Step Equation Solver.

A full-featured graphing calculator with large 2-D and enhanced 3-D color graphs to better Illustrate problems and concepts

The Formulas and Equations Library—a resource with more than 100 commonly used equations and formulas to help you identify and apply the right one for your problem

The Triangle Solver—a graphing tool that helps you explore and better understand triangles and their parts

The Unit Conversion Tool—a handy tool that quickly and easily converts units of measure including length, area, volume, weight, temperature, pressure, energy, power, velocity, and time.

Ink Handwriting Support that works with Tablet PCs and Ultra-Mobile PCs and recognizes handwritten problems.

With the Microsoft Mathematics 4.0 free download, you get:

A full-featured graphing calculator
The Formulas and Equations Library
The Triangle Solver
The Unit Conversion tool
Ink handwriting support.