Respuesta :

to make it easier convert the times all into minutes. 

2 hours 20 minutes = 120 minutes + 20 minute = 140 minutes 
4 hours 10 minutes = 240 minutes + 10 minutes = 250 minutes 

Then subtract: 

250 minutes - 140 minutes = 110 minutes 

Convert back to hours/minutes: 

110 minute = 1 hour and 50 minutes 
caylus
Hello,

you may also do it like this (see picture)
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Ver imagen caylus