Quickly Solve this riddle

7 - 4 + 3 * 0 + 1 = ?

What jumps when it walks and sits when it stands?

Which alphabet is a part of our body?

Can you find a number that lies one third of the distance between 1/3 and 2/3?

Next Number in the Series,

5, 16, 49, 104, ?

I am the largest in my family of fifty.
The youngest of our family lives separately from the rest of the family and so do I.
I am regarded as harsh and tough.
I am so large, you cut me in two equal halves,
each half would still be larger than the second largest member of the family.
Who am I?

You are playing a game with your friend Jack. There are digits from 1 to 9. You both will take turn erasing one digit and adding it to your score. The first one to score 15 points will win the game.

Would you want to play first or second?

PS: The sum should be exactly 15.

What do you call a fish without an eye?

Find the Goldfish below the given Image.

With pointed fangs I sit and wait; with piercing force I crunch out fate; grabbing victims, proclaiming might; physically joining with a single bite. What am I?