You have to put a letter on the following to make it a meaningful word. The only challenge is that you can't use 'E'.

S E Q U E N C _

If there are fifteen crows on a fence and the farmer shoots a third of them, how many crows are left?

There is a basket full of hats. Three are white and two are black. Three men, Tom, Tim, and Jim, each take a hat out of the basket and put it on their heads without seeing the hat they selected or the hats the other men selected. The men arrange themselves so Tom can see Tim and Jim’s hats, Tim can see Jim’s hat, and Jim can’t see anyone’s hat. Tom is asked what color his hat is and he says he doesn’t know. Tim is asked the same question, and he also doesn’t know. Finally, Jim is asked the question, and he does know. What colour is his hat?

What has six faces, but does not wear makeup, has twenty-one eyes, but cannot see?

I am a prime number.
The double of myself is equal to the square of me.

which number am I?

What is the word or phrase?

What kind of band never plays music?

What is the Surname of Barbie Doll?

What can you see in the middle of March and April that you can never see in any other month?

You see me once in June, twice in November, and not at all in May. What am I?