The IUPAC name of the compound ${\mathrm{CH}}_3\mathrm{CH}=\mathrm{CHCH}=\mathrm{CHC}\equiv {\mathrm{CCH}}_3$ is 

The numbering goes as follows. $\stackrel{1}{{\mathrm{CH}}_3}\stackrel{2}{\mathrm{CH}}=\stackrel{3}{\mathrm{C}}\mathrm{H}\stackrel{4}{\mathrm{C}}\mathrm{H}=\stackrel{5}{\mathrm{C}}\mathrm{HC}\equiv {\mathrm{CCH}}_3$The preference goes to a triple bond, but counting is done from the double bond end. The correct name is 2,4-octadien-6-yne.