How do the seven kings in Revelation 17 fit with Daniel's ten kings?

Les teaches that Revelation 17:9-11 must be read alongside Daniel. The seven heads are seven mountains, meaning seven nations with seven prime ministers or kings, and the woman sitting on them is the religious system. He explains the sequence: it started with ten; three lost their identity and were usurped by seven. One king is present, and another is not yet come but will continue a short space—likely another world or European leader coming in the interval. Verse 11's beast that was is the old Roman Empire, seemingly dead but returning with its attributes in place, headed by the Antichrist, who is the eighth. Les also notes Scripture's numeric values: three for the Godhead/deity, five for grace, six for man, seven for deity, and eight for that which follows the completion of seven.