It’s a quarter past 4.

16:15

It’s a quarter past 4.

Error: read digital clock as if it were an analogue clock

16:15

It’s a quarter past 4.

Error: read quarter as a number

15:45

It’s a quarter to 4.

Error: confuse ‘past’ and ‘to’

15:45

It’s a quarter to 4.

Error: confuse ‘past’ and ‘to’ and read quarter as number