In doing a calculation with the Wolfram Language, you usually go through a sequence of steps. If you want to, you can do each step on a separate line. Often, however, you will find it convenient to put several steps on the same line. You can do this simply by separating the pieces of input you want to give with semicolons.
|expr1;expr2;expr3||do several operations, and give the result of the last one|
|expr1;expr2;||do the operations, but print no output|
If you end your input with a semicolon, it is as if you are giving a sequence of operations, with an "empty" one at the end. This has the effect of making the Wolfram Language perform the operations you specify, but display no output.