What's the next in the series?

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

A seven-year-old kid challenged his classmates that he can make the number one disappear by adding something to it.

How can he do that?

I am the one who remains awake when you sleep. But I need to rest when you awake. Who Am I?

0 0 0 = 6
1 1 1 = 6
2 2 2 = 6
3 3 3 = 6
4 4 4 = 6
5 5 5 = 6
6 6 6 = 6
7 7 7 = 6
8 8 8 = 6
9 9 9 = 6

You can use any mathematical symbols in the space provided to make all above algebraic expressions true.

By moving exactly three matchsticks can you make the below equation true.It can be solved by 3 ways.

What is the next number in this matchsticks series riddle?

Can you start the fire using two pieces of wood?

Why do we preferably have round manhole covers and not square ones?

Find out the missing number in the picture attached:

Find three whole, positive numbers that have the same answer when multiplied together as when added together.