# I can't figure out how to do an simple algoritm to get the sum of two numbers

I am trying to find a solution to the problem “Two Sum” if you recognize it , and I’ve run into a problem and I cannot figure it out (Lua)

Code:

``````num = {2,7,11,15}
target = 9
current = 0
repeat
createNum1 = tonumber(num[math.random(1,#num)])
createNum2 = tonumber(num[math.random(1,#num)])
current = createNum1 + createNum2
until current == target
print(table.find(num,createNum1), table.find(num,createNum2))
``````

Error:

``````lua5.3: HelloWorld.lua:9: attempt to call a nil value (field 'find')
stack traceback:
HelloWorld.lua:9: in main chunk
[C]: in ?
``````

Not made in Studio , Thanks for the time!

it’s saying that `find` isnt a function in `table`
that might be a Luau only function

also, about your implementation, you should also check if the 2 indexes are the same. I don’t think you can use the same number twice

I already found the solution , it was kinda of unexpected , but it’s alr now, thank you for your time

Solution:

``````num = {2,7,11,15}
target = 9

local idx = {}
for i, n in ipairs(num) do
local j = idx[target - n]
if j then
print(j, i)
break
end
idx[n] = i
end
``````