Before Mount Everest was discovered, what was the highest mountain in the world?

I can be made.
I can be cracked.
I can be told.
I can be played.

Who am I?

Can you find the odd number in the following five choices?

1) 482636
2) 259807
3) 865195
4) 104739
5) 391744

What does this mean?
N
A
E
L
C

If 2 workers can complete painting 2 walls in exactly 2 hours.

How many workers would be needed to paint 18 walls in 6 hours?

You need to climb ten stairs. At every stair, you can either take one step up or you can jump two steps up.

In how many different ways you can climb 10 stairs?

It's a 7-letter word.
If we remove 1 letter from it, it remains the same.
If we remove 2 letters from it, it remains the same.
If we remove 3 letters from it, it remains the same.
If we remove all the letters from it, still it remains the same.
What is it?

I came first on earth but second on the heaven.
I also came twice in a week but found just once in a year.
I stay away from months but you can find me in February.

What am I?

I noticed one of the words in the oxford dictionary is spelled incorrectly. What about you?

Can you complete the sequence?

192, 021, 222, 324, 252, 627, 2__, 9__?