With a cow-culator! (Rimshot)
Milk and Bookies.
A dead cow! (My 5-year old made up this joke)
Because he likes to Count.
There is no difference. The joke is you just learned math.
You use a cow-culator. Or you round them up. Or any other method the commenters want.
A cow-culator! (Cue groans)
You can't lick a woman dry. Rimshot*