Solution:

The correct choice will be the option 'd'.

In each succeeding row, the previous column is reversed and the lowest digits are omitted.

Solution:

We have provided you with one of the possible solutions. However, there can be three more solutions to this problem.

Solution:

The figure shows how we have done it. If you have any other idea in mind, feel free to comment below.

Solution:

You can see how we did that in the given picture. The idea is to covert the boundaries first and then move to inner squares. If you have another solution, you can send us that or comment with it below.

Solution:

You can see how we did it in the given picture.

Solution:

We have moved the two matchsticks colored in purple and now the resultant figure contains five 1x1 squares, one 2x2 square and one 3x3 square.

Solution:

It is a baby's face as you can see in the answer picture.

Solution:

In the picture you can find the green matchsticks. We have moved them from the bottom and placed them in the middle. It was a bit tricky but now you have your desired result.

Solution:

Circle = Three
Star = Five
Triangle = Four

Solution:

3

Explanation:
Number in the series = (Top Left Number * Bottom Left Number)/(Top Right Number * Bottom Right Number)
= (30 * 2) / (4*5)
= 3