YOU GUYS ARE MISSING THE NEGATIVES.
Also, it's not meant to be done in proper math. The reason is because nobody remembers to do proper math right away anyways.
Negative two plus five equals three.
Three times eight equals twenty-four.
Twenty-four divided by six equals four.
Negative ten point five times four equals negative forty-two.
Negative forty-two divided by seven equals negative six.
Negative six plus eight equals two.
the .":0". is code talk, it means append to result (dunno how to put it any other way but that's the gist of it).
So, 4:02!