Can you arrange four 9's and use at most 2 math symbols, to make the total 100?

I am eight letters long - "12345678"
My 1234 is an atmospheric condition.
My 34567 supports a plant.
My 4567 is too appropriate.
My 45 is a friendly thank-you.
My 678 is a man's name.

What word am I?

Whats the next number in the below number sequence pattern.

Detective John was investigating a murder in China.
It was a difficult case, and John was completely stumped until he noticed a message sent to him by the killer cunningly hidden in a newspaper advertisement selling Car Licence Plates.
Detective John thought about it for a while, and when he had solved the puzzle, immediately arrested the guilty man.

Q1) How did John know the advert was a clue for him?

Q2) Solve the code and tell me who John arrested.

This is the newspaper advert (Car licence plates for sale) that Detective John saw.

Plates For Sale;

[W 05 NWO]
[H 13 HSR]
[O 05 EBM]
[D 08 UNE]
[U 10 HTY]
[N 04 BRE]
[N 16 TTE]
[I 26 LHC]
[T 10 AEE]
[I 26 CNA]
[X 22 VDA]

using four eights (8) and a one (1) and one mathematical symbol , create the number 100

What can you serve, but never eat?

When I got four, I have it none.
When I got two, I have it some.
When I got none, I have it all.

What is it?

Count the squares in the matchstick puzzle below?

What do you see in the image below

You throw me out when you want to use me and you take me in when you don't want to use me.

Who Am I?