Question

Subtract 2 hours, 20 minutes from 4 hours, 10 minutes.

2 hours, 10 minutes
1 hour, 50 minutes
1 hour, 30 minutes
1 hour, 10 minutes

Answer 1

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 

Answer 2

Hello,

you may also do it like this (see picture)
==============================