The addition of natural numbers

Operations with natural numbers I

12. Complete this seven-pointed magic star.  
  Esta unidad interactiva requiere la máquina virtual de Java J2RE.

This seven-pointed star is formed with natural numbers from 0 to 20.

The sum of the three numbers of each segment is 30.

To complete the star you may put the numbers on the segments where only one is needed.

There are 168 different seven-pointed stars. Every time you click on Init a new star will appear at random.

  Eduardo Barbero Corral
Spanish Ministry of Education. Year 2007

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