## Task 3

Petra, Holger, and Ines want to give a pennant chain to Soviet soldiers. Petra and Holger stick 9 pennants together. Ines brings 4 pennants.

How many pennants can they attach to the pennant chain?
$9+4=13$; You can attach 13 flags to the chain.

### 10.11.2 2nd Round 1975, Class 1