It’s 18 to 7 (Official clock system).

06:42

It’s 18 to 7.

Correct answer

06:43

It’s 17 to 7.

Error: 1 minute later

05:50

It’s 10 to 6.

Error: read minutes starting from hour markings and adding minutes

08:30

It’s half past 8.

Error: confuse hour and minute hands