In my school we’ve occasionally had a problem with scientific graphing calculators growing legs and walking away for good. I’m sure we’re not the only school to have that problem. One possible solution to the problem of disappearing calculators is to have students use calculators on their laptops, netbooks, or tablets. Here are five free calculators that you can either use online or install on your computer.
Microsoft offers scientific calculator that you can download for free (Windows only). Microsoft Mathematics 4.0 is a graphing calculator that plots in 2D and 3D. Of course, the calculator does many other functions such as solving inequalities, converting units of measure, and performing matrix and vector operations.
Encalc is a free online scientific calculator. Encalc describes itself on its homepage as follows, “Encalc is an online scientific calculator. Its strength lies in its ability handle units and dimensional analysis, to define variables and its large database of constants. Parenthesis and scientific formulas are also supported.” One of the features that I really like about Encalc are the explanations of how different variables and constants function within an equation or formula.
Web2.0calc is a free online scientific calculator. While it won’t replace the TI-84 Plus, it can do what your average high school student needs it to do. The best part is, you don’t have to use it on the Web2.0calc site because they offer three widgets that you can use to embed the calculator into your own blog or website.
Speed Crunch is a free scientific calculator application for Windows, Mac, and Linux operating systems. Speed Crunch performs all of the functions necessary for high school Algebra and Geometry courses except graphing. In addition to performing all of these functions, Speed Crunch has a “math book” containing commonly used equations and formulas. One Speed Crunch feature that appealed to me from a design standpoint is the color coding of equations to differentiate between constants and variables.
Graph.tk is a free online graphing utility that I found in the Google Chrome Web Store. Graph.tk allows you to plot multiple functions through its dynamically resizing grid. To graph an equation on Graph.tk just click the “+” symbol to enter a new equation. Click here to watch a short video of Graph.tk in use. One thing that the video doesn’t show and isn’t clear the first time you use Graph.tk is that you need to delete the existing default equations before you start.
