McGraw Hill does not provide answers for its textbooks online. However, MathHelp offers customized lessons to help understand specific math problems in about 200 popular textbooks, while Chegg offers interactive solutions to problems in textbooks about numerous subjects for $14.95 a month as of May 2015.
MathHelp provides math lessons and practice for middle school, high school and college classes as well as tests like the GRE and SAT. By entering a textbook name and page on the site, users can find the lesson that will teach them the skills necessary to solve a specific problem.
Chegg offers odd and even solutions for problems in over 9,000 textbooks covering subjects as diverse as biology and Spanish. While the site also includes other features such as online tutoring, it does require a subscription to use, although free trials are available.