6. (6 points) Two rectangles, each 4 cm long and 2 cm wide, are joined together (without overlapping) to form a new rectangle. The perimeter of the new rectangle is $\qquad$ cm, or $\qquad$ cm.
【Analysis】According to the method of combining two new rectangles into a larger rectangle, we can get: the length and width of the new rectangle are $4+4=8$ cm, 2 cm; or 4 cm, 4 cm, so the perimeter of the new rectangle is $(2+4+4) \times 2=20 \mathrm{~cm}$, or $4 \times 4$ $=16 \mathrm{~cm}$.

【Solution】Solution: $(4+4+2) \times 2$,
$$
\begin{array}{l}
=10 \times 2, \\
=20 \text { (cm), } \\
4 \times 4=16 \text { (cm), }
\end{array}
$$

Answer: The perimeter of the new rectangle formed by combining is 20 cm or 16 cm.
Therefore, the answer is: $20 ; 16$.
【Comment】The key is to know that there are two ways to combine two rectangles into one, and then use the perimeter formula for a rectangle $C=(a+b) \times 2$ to solve the problem.