Hey there :)
We know an hour consists of 60 minutes
If he has watched 52 minutes, that is 8 minutes away from an hour
60 - 52 = 8
And since the movie is 1 hour and 37 minutes, he has 8 + 37 = 45 minutes left to watch
OR
1 hour = 60 minutes
60 + 37 = 97
97 - 52 = 45
He has 45 minuted of movie left to watch
