Dozens of, thousands of: hàng chục, hàng ngàn / nghìn

Put hàng before chục (ten), trăm (hundred), ngàn (thousand) or triệu (million) to say "dozens of", "hundreds of", "thousands of", "millions of": hàng chục người (dozens of people), hàng trăm món (hundreds of dishes), hàng ngàn du khách (thousands of tourists; in Hà Nội, hàng nghìn). No number goes in front, and no những or các: hàng already means "many of them".

It gives a large, rough number, often to show scale or surprise: Em gửi hàng chục email rồi mà chưa ai trả lời. I've sent dozens of emails and nobody has answered. Vietnamese counts in tens here, where English counts in dozens.

You can stack two for bigger amounts: hàng chục ngàn (tens of thousands), hàng trăm triệu (hundreds of millions). In the news you'll also see hàng vạn (tens of thousands), an older word that sounds Northern; Saigon speech says hàng chục ngàn.

Don't mix this up with hàng before a time word, which means "every": hàng ngày (every day), hàng tuần (every week). Before a number word, it means "many".