On a day when offensive stars Calvin Johnson and Reggie Bush could not play due to injuries, the Lions defense had to step up, and it did in a big way. Detroit sacked Vikings rookie quarterback Teddy Bridgewater eight times, harassed him into throwing three interceptions, and held the Vikings scoreless until late in the fourth quarter. The Lions got on the board in the first quarter with a 9-yard TD pass from Matthew Stafford to Theo Riddick. Matt Prater, acquired during the week to replace the struggling Alex Henery, made good on a 52-yard field goal near the end of the first half to give the Lions a 10-0 lead. After a scoreless third quarter, Detroit upped its lead to 17-0 on a 1-yard TD plunge by Joique Bell. Blair Walsh got the Vikings on the board with a 40-yard field goal, making the final score 17-3.

Based on the above article, answer a question. How many more points did the Lions score in the first half than the second?
3