"The revolutionary calculator that shows the answer only when you also enter a suitable mental estimate." (I have no connection with this company or product.)
There are plenty of calculator apps in Google Play, but IDEAL WebMath is different because it shows students how to solve a problem. IDEAL WebMath can help students with addition, subtraction, multiplication, division, comparing fractions, ratios, proportions, place values, and rounding.
A nice online maths tool for working out percentages. Just input the numbers. You can even embed it into your site.
http://ictmagic.wikispaces.com/Maths
kanakku is a free web 2.0 application that is a combination of a spreadsheet and a calculator. This application is designed to be used on either IE 7+ or Firefox (Safari seems to be compatible, but further testing is ongoing). All operating systems that use these browsers should be able to use this Website.
Math calculators are very helpful for students in solving their math problems. From algebra to geometry, trigonometry to statistics, these calculators are very helpful. Teachers and Parents also get much help from these calculators if they don't find the solution to some difficult math problems.
"Street-Fighting Mathematics:
The Art of Educated Guessing and Opportunistic Problem Solving" by
Sanjoy Mahajan, published in 2010. "Mahajan describes six tools: dimensional analysis, easy cases, lumping, picture proofs, successive approximation, and reasoning by analogy. Illustrating each tool with numerous examples, he carefully separates the tool-the general principle-from the particular application so that the reader can most easily grasp the tool itself to use on problems of particular interest." Available as a free download (Creative Commons License), .pdf): http://mitpress.mit.edu/books/full_pdfs/Street-Fighting_Mathematics.pdf
A 10 part series by Professor Marcus du Satuoy, University of Oxford, "argues that mathematics is the driving force behind modern science. Ten fifteen minute podcasts that reveal the personalities behind the calculations from Newton to the present day. How do these masters of abstraction find a role in the real world?"