How can one talk without saying a single word?

Can you find the next number in the below sequence
3 , 7 , 10 , 11 , 12 , 17 ?

What's the next in the series?

H, Be, F, S, Mn, Kr, In, Gd, Tl, ?

There are a number of books on a shelf. If one book is the 4th from the left and 6th from the right, how many books are on the shelf?

Can you solve the below tricky visual equation?

The person who makes it has no need for it. He who purchases it does not use it. The person who does use it does not know they are. What is it?

You are mixing a mixture of cement and Sand with five gallons of water. You have a garden hose giving you all the water you need. The problem is that you only have a four-gallon bucket and a seven-gallon bucket and neither has graduation marks. Find a method to measure five gallons.

A word I know has six letters it contains, remove one letter and 12 remain. What is it?

What does an Island and the letter T have in common?

Let's play a word game. Following are some meaningless words that can be completed by adding random letters on either side of the word.

For example, the word "rdo" can be formed into "pardon".

Using the same technique, can you complete the given words?
ecalc
airb
rinci
tibac
uidel
gorit
igna
eyho