The phrase "chosen number" refers to a specific number that someone has selected or picked.
Sentences with «chosen number»
One also has a chance of choosing the number of years covered. (coverfox.com)
Simply choose a number for the children to write in the middle box (can be differentiated) and the children answer the questions surrounding it. (tes.com)
After selecting their whole fish, customers can customize their meal by choosing any number of preparation techniques. (fb101.com)