'Thousand' in the Bible

Then those who gladly received his word were baptized. There were added that day about three thousand souls.

But many of those who heard the word believed, and the number of the men came to be about five thousand.

Many of those who practiced magical arts brought their books together and burned them in the sight of all. They counted the price of them, and found it to be fifty thousand pieces of silver.

Aren't you then the Egyptian, who before these days stirred up to sedition and led out into the wilderness the four thousand men of the Assassins?"