To rewrite \( 33 + 66 \) using their greatest common factor (GCF) and multiplication, we first need to determine the GCF of 33 and 66.
- The factors of 33 are: 1, 3, 11, 33
- The factors of 66 are: 1, 2, 3, 6, 11, 22, 33, 66
The greatest common factor is 33.
Now, we can factor 33 out of \( 33 + 66 \):
\[ 33 + 66 = 33 + 2 \times 33 = 33(1 + 2) \]
So, the expression \( 33 + 66 \) can be rewritten as:
\[ 33(1 + 2) \]