Behold; if it goes up by the way of its own border to Beth-shemesh, then he has done us this great evil: but if not, then we shall know that it is not his hand that struck us; it was a chance that happened to us."
Actually it should read, "Of the city, or of the people of fifty thousand, seventy were slain, seventy men were slain." In other words, of that population of the area, approximately fifty thousand people, seventy of them were slain.