Wolfram Research, Inc.
1.4.8 Controlling the Display of Large Expressions
When you do symbolic calculations, it is quite easy to end up with extremely complicated expressions. Often, you will not even want to see the complete result of a computation.
If you end your input with a semicolon, Mathematica will do the computation you asked for, but will not display the result. You can nevertheless use % or Out[n] to refer to the result.
Even though you may not want to see the whole result from a computation, you often do need to see its basic form. You can use Short to display the outline of an expression, omitting some of the terms.
Ending your input with ; stops Mathematica from displaying the complicated result of the computation.
In:= Expand[(x + 5 y + 10)^8] ;
You can still refer to the result as %. //Short displays a one-line outline of the result. The <<n>> stands for n terms that have been left out.
In:= % //Short
This shows a three-line version of the expression. More parts are now visible.
In:= Short[%, 3]
This gives the total number of terms in the sum.
Some ways to shorten your output.