A dozen
Its a trick question there are always 12 items in a dozen, it does not matter what they are. so a dozen stamps is 12 no matter what.
There are 12
12 stamps (a dozen means 12)
12
2
2 and a half.
12
You can purchase 1 cent or 2 cent stamps.
41
probally just 1 or 2 42 cent stamps
In the US you can buy two 10- cent stamps, four 5-cent stamps. five 4-cent stamps, ten 2-cent stamps or twenty 1-cent stamps for 20 cents at most post office windows.