Solution:

The sun is a star.

Explanation:
Let us find out how we got there.

- Substitute a word with its antonym.
The pound is not a start.

- Eliminate one letter from one word.
The pound is not a star.

- Remove one word.
The pound is a star.

- Take out a letter and insert another in its place.
The sound is a star.

- Take out two letters from one word.
The sun is a star.

Solution:

See the colored sticks in the picture. We have moved those sticks in the position given in the second image corresponding with the color.

Solution:

Michelangelo juggles the diamonds across while crossing the bridge.

Solution:

Since the door is not visible in this picture, the bus is moving in the left direction.

Solution:

Pages 19, 20, 23, 37, 38, & 42 will also be missing

Solution:

Birbal drew another line that was larger than the pre-drawn line. Now the pre drawn line was smaller.

Solution:

If you ask the guard who always tells the truth, he would tell you the other guard would point you to the door of death. If you ask the guard who always lies, he would tell you the opposite door of the truth-telling guard and point you to the door of death. In either case, both guards will point to the door of death so you should choose the other one.

Solution:

The women is a of short stature. She can't reach the upper elevator buttons, but can push is with his umbrella.

Solution:

Put one black rock in one sack and put all the rest in the other one. In such manner you will get about 3/4 probability of surviving.

Solution:

Step 5 is invalid, because we are dividing by (x-y), and since x=y, we are thus dividing by 0. This is an invalid mathematical operation (division by 0), and so by not following basic mathematical rules

Solution:

23rd day

1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9 + 10 + 11 + 12 + 13 + 14 + 15 + 16 + 17 + 18 + 19 + 20 + 21 + 22 + 23 = 276

Thus our anniversary falls on the 23rd day of the month.

You can apply other formulas to shorten the process but that is the simplest way to do it.