# Sigma Summation and Factorial: Level Four

Numbers

3D Game

### Sum a Series of Integers and Integers Squared

Have fun learning about the Sigma *Σ* summation and factorial *!* symbols.
Tap the Play button
to *start the timer*.
For details regarding game play tap the ? icon above.
*Warning* this level can be very challenging without a
cheat sheet!

A series of questions display
below the landscape, one at a time.
Each question asks you to
find the expression which evaluates to a specific number.
Quickly tap digits, *Σ* Sigma, and *!* factorial symbols,
to form the correct expression.
As soon as you answer a question, the
next question displays.
The game's over when the timer runs out or
you've answered every question.

### Points

Digits and symbols
display below the background
as you build the expression.
Each correct selection increases
your score by `40`

points.
The maximum score for level four equals `400`

points.

Enter a name in the form below to post your score online, when the game's over.