After losing to the Seahawks on the road, the 49ers went home to take on the Rams.  In the first quarter the Rams scored first when Todd Gurley ran for a 3-yard touchdown to make it 7-0.  The Niners managed to tie it up when Brian Hoyer ran for a 9-yard touchdown to make it 7-7.  The Rams moved back into the lead when Jared Goff found Gurley on a 7-yard pass to make it 14-7.  In the second quarter, the Rams increased their lead when Greg Zuerlein kicked a 48-yard field goal to make it 17-7.  Though the Niners would come within 4 with 2 field goals of their own kicked by Robbie Gould:  from 36 and 48 yards out to make the score 17-10 and then 17-13.  Gurley then put the Rams up by double digits at halftime when he ran for a 2-yard touchdown to make it 24-13.  In the third quarter Zuerlein kicked a 19-yard field goal to make it 27-13 Rams.  The Niners then came within a touchdown when Carlos Hyde ran for one from a yard out.  Though the Rams would move up by 2 touchdowns again when Goff found Sammy Watkins on a 1-yard pass to make it 34-20.  In the fourth quarter, the Niners came within 8 when Garrett Celek caught a 1-yard pass from Hoyer (with a failed PAT) to make it 34-26.  Though again, the Rams moved up by double digits when Goff and Watkins connected again on a 13-yard pass to make it 41-26.  Finally, the Niners were able to come within two points with two more touchdowns:  Trent Taylor caught a pass from Hoyer 3 yards out to make it 41-33. In conclusion, Hyde ran for another 1-yard touchdown (with a failed 2-point conversion) to make the final score 41-39.. How many field goals did Zuerlein kick in the first half?