The function "tostring" is used to convert a numbervalue to a stringvalue.
For example:
local value = workspace.NumberValue.Value
local part = workspace.Part
part.Name = tostring(value)
Let's say that the variable "value" is identifying a NumberValue in the
workspace, and the variiable "part" is finding a "Part" in the workspace.
The "tostring()" will allow me to change the value of the numbervalue to a
stringvalue for naming my part.
The function "tonumber" is very similar to the "tostring()" function.
Tonumber performs the same function, except, it can change a string value
to a number value.
For example:
local text = workspace.StringValue.Value
local numberValue = workspace.NumberValue.Value
numberValue = tonumber(text)
Let's say that the variable "text" is finding a stringvalue under the workspace,
and the variable "numberValue" is finding a NumberValue under the workspace.
With the "tonumber()" function, I can convert the string value for the variable
"text" to a number value.
Hopefully this will help you a little bit while learning LUA.