There are two different things being given to you. Both forms of extract will have gravity points to contribute, and both will have color (Lovibond scale), even if it's not explicitly told to you. To calculate your gravity you use the points, to calculate color use the Lovibond number.

For your gravity you've got 6.6 lbs of LME and 1 lb of DME. The LME is 35 points, which is per pound in a gallon of water. The DME should be around 44 points. So you've got 6.6 * 35 + 44 / gallons, or 275/5 (assuming a 5 gallon batch) or 55 points, which translates to a SG of 1.055.

Make sense?

<edit>what tygo said