Solution:

The sleeping baby is marked in the picture below.

Solution:

3rd.

Explanation:
Rule: Take the bottom row, flip it, and put it on the top.

Solution:

20

Solution:

It can be done as shown below.

Solution:

As shown in solution picture, flip the first number and stack on the second number, you will get fish eight and triangle respectively.

Solution:

Yes.

Solution:

10.

Explanation:
Most of the people will give the answer as 6 or 3.
But the total number of holes are ten.
> 1 hole for the neck.
> 2 holes for the arms.
> 1 hole for the torso.
> 3 torn holes in the front.
> 3 torn holes in the back.

Solution:

12

Solution:

As shown in the picture below, add matchstick to make 1st + symbol as 4.

Solution:

As marked in the solution picture, all men in the background have the same face.