Is the beast only worshipped for 3½ years, not 7?

Revelation 13:4b  and they worshipped the beast, saying, Who is like unto the beast?

 5b  and power was given unto him to continue forty andtwo months.

  8 And all that dwell upon the earth shall worship him, whose names are not written in the book of life of the Lamb slain from the foundation of the world.