Coming off their win over the Cowboys the Redskins played on home ground for an interconference duel with the Texans. In the 1st quarter the Redskins scored first as kicker Graham Gano got a 41 and a 27-yard field goal. In the second quarter the Redskins fell behind with QB Matt Schaub completing a 5-yard TD pass to WR Jacoby Jones, but got the lead back when RB Clinton Portis got two 1-yard TD runs to put the Redskins up 20-7. The Texans tried to cut the lead in the third quarter as kicker Neil Rackers nailed a 47-yard field goal, but the Redskins increased their lead with QB Donovan McNabb completing a 22-yard TD pass to TE Chris Cooley. The Texans went on a scoring rally to tie the game when QB Matt Schaub made a 6-yard TD pass to WR Kevin Walter, followed in the 4th quarter by Rackers making a 43-yard field goal. Then Schaub threw a 34-yard TD pass to WR Andre Johnson. The decision was made when Rackers booted a 35-yard field goal in overtime to give the Redskins a loss.
Question: How many points were the Redskins leading by at the half?
Answer: 13