# Entering Sum in traditional form

The documentation for Sum says that it is possible to replace Sum by EscsumEsc. The limits ($i_\max$ and $i_\min$) should be entered as underscript $i=i_\min$ below $\sum$ and overscript $i_\max$ over $\sum$

Following the aforementioned rules, I entered the formula as:

 Cell[BoxData[
UnderscriptBox[
RowBox[{
OverscriptBox["\[Sum]", "10"], "q"}],
RowBox[{"q", "=", "1"}]]], "Input",
CellChangeTimes->{{3.572528196734789*^9, 3.572528215609144*^9}},
EmphasizeSyntaxErrors->True]


which gives an error

Syntax::sntxi: Incomplete expression; more input is needed .

How do I fix this?

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The easiest way to enter sums with limits is to use the keyboard shortcut EscsumtEsc (see the Advanced Math Assistant palette). Then you get a template that can be filled by tabbing between the placeholders.

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You probably entered Ctrl$, followed by Ctrl& to create the under and over scripts individually. You can see in your code that this is what happened, because of the presence of UnderscriptBox and OverscriptBox. Instead, what you need is UnderoverscriptBox, which is obtained by Ctrl$ (or Ctrl&), followed by Ctrl%. This automatically creates the opposite script and associates it as a single UnderoverscriptBox instead of separate under/over scripts.

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You appear to be entering the lower and upper limits incorrectly.

From the documentation for Sum:

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documentation specified overscript as [Ctrl]+7. Replacing with Ctrl+% works. Thanks – ipy Mar 17 '13 at 18:09