noun, noun which may take the genitive case particle 'no'
tens of thousands; several tens of thousands
Refers to an approximate number in the range of tens of thousands (roughly 20,000–90,000). Often used with の to modify a noun.
Tens of thousands of spectators gathered at the venue.
This project will cost tens of thousands of yen.
Tens of thousands of spectators gathered for the concert.
Tens of thousands of people evacuated because of the earthquake.
The repair cost tens of thousands of yen.
数千 means 'thousands', a smaller scale than 数万, which means 'tens of thousands'.
数百 means 'hundreds', a much smaller scale than 数万, which means 'tens of thousands'.
Compound of 数 (すう, 'several') and 万 (まん, 'ten thousand').