Which number should replace the question mark?

Using eight eights and addition only, can you make 1000?

A California farmer owns a beautiful pear tree. He supplies the fruit to a nearby grocery store. The store owner calls the farmer to see how much fruit is available for him to buy. The farmer knows the main trunk has 24 branches. Each branch has exactly 12 boughs and each bough has exactly 6 twigs. Since each twig bears one piece of fruit, how many plums will the farmer be able to deliver?

Use the digits from 1 up to 9 and make 100.

Follow the rules.
=> Each digit should be used only once.
=> You can only use addition.
=> For making a number, two single digits can be combined (for example, 4 and 2 can be combined to form 42 or 24)
=> A fraction can also be made by combining the two single digits (for example, 4 and 2 can be combined to form 4/2 or 2/4)

Question: how can we do this?

I have no doors but I have keys, I have no rooms but I have space, you can enter but you can’t leave! What am I?

I am lying and I always lie. Tell me whether I am lying or telling the truth.

A certain street contains 100 buildings. They are numbered from 1 to 100. How many 9's are used in these numbers?

It has a long neck, A name of a bird, Feeds on cargo of ships, It's not alive,

What is it?

When I go in I might cause pain. I cause you to spit and ask you not to swallow. I can fill your hole. What am I?

There are four 3-link chains. All you have to do is join them into a big 12-link chain. For joining two closed links, one of the links must be cut and placed onto the other link for closing.

How many minimum links will you have to cut to make the big chain?