To find the area of the Canadian football field, you need to add 3,350 square yards to the area of the American football field.
Area of Canadian football field = Area of American football field + 3,350 square yards
= 6.4×10^3 square yards + 3.35×10^3 square yards
= (6.4 + 3.35)×10^3 square yards
= 9.75×10^3 square yards
Therefore, the area of a Canadian football field is 9.75×10^3 square yards.