Chapter 2.4.3 Qalculate! ======================== Qalculate! is the default calculator shipped in Lubuntu since 25.04. Usage ----- To do simple airithmetic computations type the numbers into the field just below the toolbar. To start a calculation press :kbd:`enter` or press the :guilabel:`=` button. To add multiple numbers press :kbd:`+` or click the :guilabel:`+` button. To subtract two numbers press :kbd:`-` or click :guilabel:`-`. To multiply two numbers press :kbd:`*` or click :guilabel:`x`. To divide two numbers press :kbd:`/` or click the :guilabel:`/` button. To input decimals into Qalculate! type :kbd:`.` as the decimal point or click :guilabel:`.` To input the last answer you calculated click the :guilabel:`ANS` button. To delete the last character you typed press :kbd:`backspace` or click the :guilabel:`trash can` button. To clear all you have inputted left click the :guilabel:`Leftward pointing arrow with an x` button or press :kbd:`Escape`. To start doing an operation first use a parenthesis to do an operation first :kbd:`(` or click :guilabel:`(`. To close the operation you want to do first in order of operations use a close parenthesis so press :kbd:`)` or left click on :guilabel:`)`. To have both an open and close parentheses click the :guilabel:`(x)` button. If you have an error in your syntax an orange triangle will show up. To get more information on what your error is mouseover the orange triangle. To get more information on a button you can also mouseover that button. .. image:: qalculate-mainwindow.png Below where you type in calculations is a history of your previous calculations. To go back in your history press the :kbd:`Down arrow` key. To go one step forward in your history press the :kbd:`Up arrow` key. To move the cursor one character to the left press the :kbd:`left arrow` key or left click the :guilabel:`left arrow`. To move the cursor one arrow to the right press the :kbd:`right arrow` key or left click the :guilabel:`right arrow` key. To move the cursor to the end press the :kbd:`End` key or right click the :guilabel:`right arrow` button. To move the cursor to the start press the :kbd:`Home` key or right click the :guilabel:`left arrow` button. To copy text from Qalculate! select the text and press :kbd:`Control + C` or right click and select :menuselection:`Copy`. To cut the text from Qalcualate! press :kbd:`Control +X` or right click and select :menuselection:`Cut`. To past text press :kbd:`Control +V` or right click and select :menuselection:`Paste`. To store a value in calculator memory left click the :guilabel:`MS` button. To later get the same value out of the calculator left click the :guilabel:`MR` button. To clear the memory stored in the calculator press the :guilabel:`MC` button. Qalculate also does many operations with fractions. To input 1/2 into something you can middle click on the :guilabel:`2` button. Similarly to input 1/3 middle click on :guilabel:`3` and for 1/4 middle click on :guilabel:`4` and so on. Qalculate will also simplify fractions if you type them in so if you type in 4/16 Qalculate! will reduce it to 1/4 and then also provide a decimal answer with a :guilabel:`=` sign for an exact value or an :guilabel:`≈` for an approximate solution if not exact. Qalculate! will also let you add, subtract, multiply, divide, or more advanced fractions with fractions and still show the result as fractions. To exponentiate a base number to a power left click x :sup:`y` or type :kbd:`^`. To square a number right click x :sup:`y` or type :kbd:`sq()` around what you want to square. To raise e to a power middle click x :sup:`y` or type :kbd:`exp()` around what power you want to raise e to. To take the square root of something left click the :guilabel:`√` button or insert a :kbd:`√` character. To take the cube root of something right click the :guilabel:`√` button or type :kbd:`cbrt()`. To take the nth root of something middle click on the :guilabel:`√` button or type :kbd:`root( , )` where the first thing is what you are taking the root of and the second is which root to take. To take a natural lograrithm left click on the :guilabel:`ln` button or type in :kbd:`ln()`. To take a logarithim on base 10 right click on the :guilabel:`ln()` button or type in :kbd:`log10()`. To take a logarithim with base n middle click on :guilabel:`ln` and then input your base. Version ------- Lubuntu ships with version 5.5.0 of Qalculate! How to Launch ------------- To launch Qalculate! :menuselection:`Accessories --> Qalculate! (Qt)` or run .. code :: qualculate-qt from the command line.