Which words are being defined?

1. The place where you throw away paper you don’t want. bin
2. People you work with.  .
3. Something you put on a wall which tells you the date.  .
4. A book where you write down appointments and things you have to do.  .
5. A piece of paper which shows a customer what they have bought and what they must pay.  .
6. An electronic device that helps you to add up numbers and do maths.  .
7. An informal word meaning ‘lots’.  .