Solution:

72(18*4)

Solution:

The first figure tells you where you have to make the cut in the paper. Now you have two pieces of paper. If you rotate the right piece to 180 degrees, you will get what is shown in the figure two. Now the hole is in the center of the paper.

Solution:

The ten difference are as follows:
1) The direction of the paper plane is changed.
2) The amount of white flowers is different.
3) There is one extra bird.
4) The shoes of the girl are plain white.
5) One snail is missing from the picture.
6) There is one extra butterfly.
7) One apple is missing from the picture.
8) Different number of dots of the bow of the girl.
9) There is one extra plant.
10) If you notice, an airplane is missing from the ground.

Solution:

Two wrong dont make a right

Solution:

Pi(pi-symbol) + Rate (of acceleration)
= Pirate

Solution:

For(4) + a + change(delta/change symbol)
= For a change

Solution:

Route(Root symbol) + 66
= Route66

Solution:

40 triangles

16 + (8x2) + (4x2) + (1x2) + (1x2)

Solution:

20 Triangles

Explanation:
Let us consider the smallest side of the triangle as 1 cm.
Now count and you will find out that we have 1 + 5 + 5 + 1 = 12 triangles with the side 1 cm.
Number of triangles with side 2 cm = 1 + 2 (triangles facing upwards) + 1 + 2 (triangles facing downwards = 6 triangles
Number of triangles with side 3 cm = 2 (a triangle facing upwards + a triangle facing downwards)

Summing them up, we have 20 triangles in total.

Solution:

This problem can be solved with similar triangles property.
The White triangle is similar to the Red one
Now Ratio of sides is 2:3 (as ratio of areas = ratio of based if the height is same)
Seeking that, White triangle = 9/4 * Yellow triangle = 9/2
Following all the above, the Green region = 5.5 units