john is playing a game in which he tries to obtain the highest number possible. he must put the symbols , $\times$, and - (plus, times, and minus) in the following blanks, using each symbol exactly once: \[ 2 \underline{\hphantom{8}} 4 \underline{\hphantom{8}} 6 \underline{\hphantom{8}} 8. \]john cannot use parentheses or rearrange the numbers. what is the highest possible number that john could obtain?
