Time sheet - activity 1

ajax manufacturing, inc.
300 south detroit ave.
anytown, oh 85226

employee name:

hours
dec. 8 a.: 30 p.½
dec. 8 a.: 30 p. 1/2
dec. 8 a. p./2 1/2
dec. : 30 a.: 30 p./2 1/2
dec. : 30 a. p. 1/2
dec. a. p.
dec. 7 a

somehow i am off by 2/12 hours. can someone tell me why?