To find the area of a Canadian football field, we first need to calculate it based on the area of an American football field and the additional area specified.
- The area of an American football field is given as \( 6.4 \times 10^3 \) square yards.
- The additional area for a Canadian football field is \( 3,350 \) square yards.
Now, we can perform the calculation:
\[ \text{Area of Canadian football field} = \text{Area of American football field} + \text{Additional area} \] \[ = 6.4 \times 10^3 + 3,350 \]
To combine these, we need to express \( 3,350 \) in scientific notation.
\[ 3,350 = 3.35 \times 10^3 \]
Now we can add the two areas together:
\[ 6.4 \times 10^3 + 3.35 \times 10^3 = (6.4 + 3.35) \times 10^3 = 9.75 \times 10^3 \]
Thus, the area of a Canadian football field is \( 9.75 \times 10^3 \) square yards.
The final answer is:
\[ \boxed{9.75 \times 10^3} \text{ square yards} \]