Wolfram Alpha is a powerful computation engine. Kids can type in math problems, definitions and equations. The tool will do the computation and give detailed answers in a new tab. For example, if kids type “calculate the area of a circle," the tool will bring up a formula where they can input the radius and get an answer. The Pro version will show a step-by-step solution for the problem.
Search engines like Google can also compute answers and give formulas. But this tool does it without giving all the search results, which can be distracting.
Price: Free (Pro version for students is $4.95/month)