Răspuns :
6,40-22,35=7 ore si 45 minute 23,35-1 h 00,45-2 h 01,45-3 h 02,45-4 h 03,45-5 h 04,45-6 h 05,45-7 h 06,45-8 h (8 h-5 min=7 h,55 min.)
24ore-22ore 35min=1ora 25min(cat a dormit pana la miezul noptii)
1ora 25min+6ore 40min=8ore 5min(cat a dormit in total)
1ora 25min+6ore 40min=8ore 5min(cat a dormit in total)