Your answer, "7,000", is not correct.
The correct answer to
How many horsemen did David take from Hadadezer?
is
700
as shown by
2 Samuel 8:4
which is
- KJV
- And David took from him a thousand chariots, and seven hundred horsemen, and twenty thousand footmen: and David houghed all the chariot horses, but reserved of them for an hundred chariots.
- NIV
- David captured a thousand of his chariots, seven thousand charioteers {Septuagint (see also Dead Sea Scrolls and 1 Chron. 18:4); Masoretic Text captured seventeen hundred of his charioteers} and twenty thousand foot soldiers. He hamstrung all but a hundred of the chariot horses.