Financial Literacy/ How to Calculate Weekly Time Cards of Hrs/Mins/ and fractions ASAP?

I've 2 problems that show work but, I'm not exactly sure that I completely understand, nor where fractions came from. I need a step by step of how to calculate exactly with minutes and fractions within hours. Find the total number of hours for each person. •Reggie Blanco worked from 8:00 AM to 10:45 AM... show more I've 2 problems that show work but, I'm not exactly sure that I completely understand, nor where fractions came from. I need a step by step of how to calculate exactly with minutes and fractions within hours.

Find the total number of hours for each person.

•Reggie Blanco worked from 8:00 AM to 10:45 AM and from 12:15 PM to 4:15 PM.
•2 ¾ + 4 = 6 ¾

•Ruth Anderson worked from 7:30 AM to 11:55 AM and from 1:00 PM to 4:50 PM.
•4 ½ + 3 ¾ = 8 ¼

Could some please explain this to me thoroughly?
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