http://mathforum.org/k12/mathtips/beatcalc.html  BEATCALC: Beat the Calculator. (5-12) INTERACTIVE This site offers more than 300 mental calculation tricks or shortcuts.  Each contains a clear explanation and a sample problem.  This site also includes practice problems to accompany these shortcuts. 

www.calculator.com Calulators.  This site has various online calculators that anyone can use.

www.ifigure.com  The Inflation Calculator from iFigure.     iFigure provides links to online calculators and worksheets. These are interactive, educational tools that provide information to help in planning, solving and making decisions for a multitude of problems and tasks that come up daily, such as buying a home, checking on your health, investing money, figuring business profits, making statistical comparisons, or calculating pump pressure.

http://www.dadsworksheets.com/fraction-calculator.html Dads Online Fraction Calculator

https://www.desmos.com/ Desmos  Desmos wants to help every student learn math and love learning math. But “every student” is a lot of students so we create digital math tools and let the Internet take them to anyone who wants them  We built the best-in-class HTML5 Desmos graphing calculator, which millions of students around the world use for free. That calculator catches stellar reviews in app stores and from happy users on Twitter. We also create activities on top of that calculator, helping students use a powerful tool to experience all the curiosity, beauty, and sense that math has to offer. Those activities were used so often by so many teachers around the world that we decided to create an Activity Builder, helping every teacher create digital math activities that equal and exceed the activities we create ourselves.

https://www.chegg.com/math-solver Math Problem Solver & Calculator

www.education.ti.com TI-84 Plus Silver Edition Fully loaded with a built-in USB port, an improved display, many preloaded Apps, and much more, the maximum performance TI-84 Plus Silver Edition is 100% compatible, keystroke-for-keystroke with the TI-83 Plus family

www.timezoneconverter.com Time Zone Converter.  Find out the time anywhere in the world with the Time Zone Converter!