Imagine that you are visiting China and while there decide to video chat with your family back in the U$.$S$.$ How would you calculate the time difference between the U$.$S$.$ and China across the Pacific Ocean, so as to avoid calling while your family is asleep?

Added one hour for each time zone and add one day for the International Date Line

Add one hour for each time zone and subtract one day for the International Date Line

Subtract one hour for each time zone and subtract one day for the International Date Line

Subtract one hour for each time zone and add one day for the International Date Line