If you are looking for a website that explains and defines subtraction with decimals you have arrived at an excellent resource. There are even practice problems at the very end of the lesson.

This website from The Math Page explains some helpful hints about how to do mental math.

If you are looking for a website that explains and defines the basics of mental multiplication with helpful hints then you have arrived at an excellent resource. There are even practice problems at the very end of the lesson.

This website explains and defines basic subtraction. There are practice problems at the very end of this lesson.

Here is a site that clearly and thoroughly explains the graphs of the major mathematical functions. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains how to solve quadratic equations by completing the square. The quadratic formula is derived using this method on this page. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains functions and function notation. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains how to find and graph inverse functions. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains logarithms and their properties. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains quadratic functions, including graphing functions and solving equations using factoring. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains how to find the roots of polynomials of degree greater than two. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains rational and irrational numbers as subsets of the real number system. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains how to find the roots, or zeroes, of a polynomial. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains how to find the roots of polynomials of degree greater than two. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains the symmetry of even and odd functions and how to test for these types of symmetry. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains how to divide a polynomial by a binomial using synthetic division. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Clearly and thoroughly explains the graphs of logarithmic and exponential functions. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains the unit circle and all six trigonometric functions of all quadrantal angles. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.

Here is a site that clearly and thoroughly explains arc length and its relationship to radian measure of angles. There are example problems solved, problems for the student to attempt, and answers to the student problems. Point this site out to students who have been absent or who need additional instruction on this or many other topics.