Expected number error and slot changing problem

ok so i have this program working pretty well but when i run it it only build one layer of 25 blocks,= then it turns stops and givers me an error that says turtle:22: Expected number. and my Function Check() wasnt working when i had it working before, please help me with these two problems.

here is the program

function place()
turtle.back()
turtle.placeDown()
end

function turn()
turtle.back()
turtle.turnLeft()
end

function check() –this makes it change its slot if it has less than 20 in its current slot
turtle.select(x)
turtle.getItemCount(x)

while turtle.getItemCout(x) < 20 do
x = (x)=1
turtle.select(x)
end
end

–Main Program
local x
x = 1
local levels
levels = 0
term.write("How many levels should be created:")
levels = read()
for i =1, levels do

for i =1, 25 do
place()
end
turn()
check()
for i =1, 25 do
place()
end
turn()
check()
for i =1, 25 do
place()
end
turn()
check()
for i =1, 25 do
place()
end
turn()
turtle.up()
end

levels = read()

try

levels = tonumber(read()) – converts the information that's entered into a number if possible

use code tags

["code"]
#your code here
["/code"]

Also, I would pass and return variables to and from your functions:

function check(x)
 turtle.select(x)
 local amount = turtle.getItemCount()
 return amount
end