Son las diez y media.
Half past ten is 30 minutes after 10 o'clock. (10:30)
Diez
"Son las diez y media"
Quarter to 10.
The ordinal number for ten in Spanish is "décimo"
one hour and ten minuts
Diez y media means "ten-thirty" in Spanish. It refers to the time of 10:30 on a clock or watch.
10 1/2
10:45
Seven past ten
Veintiún mil