The calculator is easy to use. You will find below the different keys of the calculator and their function : : add           : subtract    : multiply    : divide       : reset ("C" for "Clear") : the negative sign. Allows you to make a negative number. Enter the number then (-). Example : To perform the operation -5 + 2 = -3, you must type : "5" then "(-)" then "+" then 2 then "=" : 1 divide by the number typed Example : To perform the mathematical calculation 1/5, you must type the following operation on the keys of the calculator : "5" then "1 / x" then "=", this gives the result 0.2 The keys to use the calculator memory are : Example : M + : addition of data in memory M- : subtract data from memory MR : recall of the number recorded in the memory Let's take an example of using a calculator with a number in memory : To calculate "3 x 8 - 6 x 2 + 12 x 3 =", use the keys below of the calculator : "3" then "X" then "8" then "=" then "M+" "6" then "X" then "2" then "=" then "M-" "12" then "X" then "3" then "=" then "M+" "MR" to display the result In our example the result displayed is 48. Indeed, 3 x 8 - 6 x 2 + 12 x 3 = 24 - 12 + 36 = 48 : percentage
 Definition of a calculator A calculator is a machine designed to perform mathematical operations. It makes it possible to simplify and make the calculations more reliable. History of calculators It is difficult to define a starting point in the history of calculators. Indeed, Humanity counts from the beginning. We originally counted with our fingers. Calculation tables were used in Mesopotamia, then the invention of the mechanical calculator. The first electronic calculators were invented in the 1960s.