numeral
fifteen
A1
Means 'fifteen', the cardinal numeral for 15 used in counting and quantities. Primary translation: fifteen. Forms compounds (fünfzehnmal). Ordinal is 'fünfzehnte'. As a standalone numeral it is invariable but can take adjective endings when used attributively. Commonly used for ages and counts.
Examples
Sie ist fünfzehn Jahre alt.
She is fifteen years old.
Die Schule erhielt fünfzehn neue Bücher, nachdem die Stiftung eine Spende bewilligt hatte.
The school received fifteen new books after the foundation had approved a donation.
Details
Mnemonics
Picture a classroom of fifteen students in three rows of five
think 'fünf' + 'zehn' = 5 + 10 = 15; say 'fünf-ten' in your head