Links to great math resources including Inside Mathematics, frequently cited as the best website for used for Algebra classrooms and FluidMath for exploring graphs and graphing equations
Testing a Claim project based lesson investigates the statement that a can of mixed nuts contains "less than 50% peanuts". Looks at differences in percents based on number, weight, calories, etc. Good to use with spreadsheet to manipulate data
Interactive page to investigate whether given conditions guarantee congruent triangles. Also has questions and answers and video links if students need extra help.