18 This calls for wisdom. Let the person who has insight calculate the number of the beast, for it is the number of a man.a That number is 666.

Read Revelation 13:18 Using Other Translations

Here is wisdom. Let him that hath understanding count the number of the beast: for it is the number of a man; and his number is Six hundred threescore and six.
This calls for wisdom: let the one who has understanding calculate the number of the beast, for it is the number of a man, and his number is 666.
Wisdom is needed here. Let the one with understanding solve the meaning of the number of the beast, for it is the number of a man. His number is 666.