operate.

opera
rate
per
rat
at
ate
era
ope
op
a

I am a shadow.

On day 10 it will reach the top.
(9 + 3) = 12

Two. ‘A’ & ‘Dictionary’

Wheat.

T (the letter 't' is added to the front 'here' to spell 'there').

A hill is hard to get up, a pill is hard to get down.

It will get wet.

Pencil lead.

485, 1456
(x/2, *3+1, /2, *3+1 …)

Because they are always stuffed.

16
The words mean n/2 - 3 = 5 => n/2 = 8 => n = 16