There are 60 minutes in one hour. If we are trying to find how many minutes are in 4 hours and 30 minutes, we first need to find out how many minutes are in 4 hours.
To do that, we just need to multiply the amount of minutes in an hour by the amount of hours we have.
60 * 4 = 240
Then, we just add the remaining 30 minutes.
240 + 30 = 270
There are 270 minutes in 4 hours and 30 minutes.
Hope that helped! =)