8. (10 points) As shown in the figure, Leilei used 12 small sticks to form a $3 \times 3$ square, and Fanfan used 9 small sticks to cut it into 3 $1 \times 2$ small rectangles and 3 $1 \times 1$ small squares. If Leilei used 40 small sticks to form an $8 \times 12$ rectangle, then Fanfan needs to use $\qquad$ small sticks to cut it into 40 small rectangles, each of which is either $1 \times 2$ or $1 \times 3$.
【Solution】Solution: According to the analysis, assuming that the 40 small rectangles are all $1 \times 3$, then the total area is $40 \times 3=120$, and the area of the rectangle is $8 \times 12=96$,
so the number of $1 \times 2$ small rectangles is $(120-96) \div(3-2)=24$, and the number of $1 \times 3$ small rectangles is $40-24=16$. The total perimeter of these small rectangles is: $8 \times 16+6 \times 24=272$,

excluding the outermost perimeter of the rectangle, each side length is located in two small rectangles, so the total length added inside the rectangle is:
$(272-40) \div 2=116$. That is, 116 sticks need to be placed.
Therefore, the answer is: 116.