'Upward' in the Bible

Now the Levites were numbered from the age of thirty years and upward: and their number by their polls, man by man, was thirty and eight thousand.

These were the sons of Levi after the house of their fathers; even the chief of the fathers, as they were counted by number of names by their polls, that did the work for the service of the house of the LORD, from the age of twenty years and upward.

Since, according to David's final instructions, the list above contains the total number of descendants of Levi from the age of 20 years and upward,