The action assigned to shortcut keys can be different in different applications. In the case of Microsoft Excel, Ctrl+1 is a useful shortcut to the format dialog, where you can assign cell formats, borders, etc.
Ctrl + 1
It saves the file.
ctrl an plus zoom the screen in an ctrl minus dezooms it
it is used to make a new slide
It means that you press the Ctrl key and holding it down, press the F1 key to perform a certain function on a personal computer and the function you perform depends on the context and the program running etc.
It lets you format the cell
ctrl shift - reverses the effect of ctrl shift =
ctrl plus r reloads a webpage.
It is because Ctrl+P is reserved for print. The use of Ctrl+V may be to make sure that the undo, cut, copy and pate function keys are adjacent to each other.
The function of <Ctrl>D is to indicate "End of Transmission". It is the ASCII EOT code. Some run-time libraries and unix shells can use it when reading from standard input to signal the end of the message.
CTRL + 1 = First Tab Change the 1 with whatever other tab, and it switches to that tab.
It makes what is on the screen bigger. Another way to do it is ctrl + plus or ctrl + scroll wheel up/down.