How would I find inventory slots next to one i'm hovering?

I can't even wrap my head around it because i'm not sure where to start the math.

An explanation will be enough, no need to show anything.

This is my starting code(if you're curious, nothing right now though), what i'm trying to do is a path of exile/diablo style inventory.

--Services
local RunService = game:GetService("RunService")
--Variables
local player = game.Players.LocalPlayer
local mouse = player:GetMouse()
--Inv

local slots = script.Parent.Slots
local getSlots = slots:GetChildren()
	local mouseSizeX = 1
	local mouseSizeY = 1
	local columns = 12
	local rows = 5
	local pickup = script.Parent.Parent.Pickup
		local pickupX = pickup.SizeX.Value
		local pickupY = pickup.SizeY.Value
		local modifiers = pickup.Modifiers

local items = script.Parent.Items
local characterUI = script.Parent.Character

mouse.Move:Connect(function()
	for i = 1, #getSlots do
		if getSlots[i].ClassName ~= "UIGridLayout" then
			getSlots[i].MouseEnter:Connect(function()
				if pickupX > 1 or pickupY > 1 then
					mouseSizeX = pickupX
					mouseSizeY = pickupY
				elseif pickupX == 1 and pickupY == 1 then
					mouseSizeX = 1
					mouseSizeY = 1
				end
				getSlots[i].ImageColor3 = Color3.fromRGB(225,225,225)
				if getSlots[i].ImageColor3 == Color3.fromRGB(225,225,225) then
					--34Y difference in each slot
					--34.5X to 34.6X difference in each slot
					print(getSlots[i].AbsolutePosition)
					
					
				end
			end)
			getSlots[i].MouseLeave:Connect(function()
				getSlots[i].ImageColor3 = Color3.fromRGB(255,255,255)
			end)
		end
	end
end)