Simplify the following text for a Grade 9 native English-speaking person.
Original: DÃ 1\/4 rer made large numbers of other practice drawings , especially for his paintings and engravings , and many survive , most famously the Praying Hands ( 1508 Albertina , Vienna ) .
Simplified: DÃ 1\/4 rer made large numbers of preparatory drawings , especially for his paintings and engravings , and many survive , most famously the Betende HÃ nde ( engl . Praying Hands , c. 1508 Albertina , Vienna ) , a study for an apostle in the Heller altarpiece .