Hi Sophiee, Dougg, the 490 years speaks about the seventy years of exile that have passed sine the Destruction of the First Temple (see Daniel 9:2-3) until his vision and the entire 420 year period of the Second Temple (Rashi). 490 years.

No disrespect to Mr. Rashi, but the breakdown of the 490 years given in the answer to Daniel's prayer delivered by the angel is not 70 plus 420, but 49 plus 434 with the one week, the final 7 years, left futher broken down into two parts.