First find the area of the first patch: 6 inches * 7 inches = <<6*7=42>>42 inches
Then find the area of the second patch: 5 inches * 5 inches = <<5*5=25>>25 inches
Then add those two amounts to find the total area Jason needs to cover: 42 inches + 25 inches = <<42+25=67>>67 inches
Then multiply that area by the number of grams per square inch to find the total amount of sand needed: 67 inches * 3 grams/square inch = <<67*3=201>>201 grams
#### 201