1 lb plain table sugar or dry extract will raise the gravity in 5 gallons by .009 points.
1 lb of LME will raise the gravity in 5 gallons by .007 points.
But ...... you will be diluting the addition, so actualy increase in effective OG will depend on the gravity of the original beer and the amount of water you dilute. For example (I will work in gallons).
OG = 1.0XX (lets say 1.050)
Volume in the fermenter is 5.0 gallons.
Therefore total gravity points at the start of fermentation would be 50 x 5.0 = 250
You add 1 lb of sugar or dry extract (gravity points = 46 ......... 1 lb of LME would be 36).
You dilute the sugar/dry extract in 2 pints of water or 0.25 gallons.
Total new gravity points = 250 + 46 = 296.
New 'effective' OG = 296/5.25 = 56 (or 1.056)