diff --git a/Day_1/Tasks_day_1.jl b/Day_1/Tasks_day_1.jl
new file mode 100644
index 0000000..33de946
--- /dev/null
+++ b/Day_1/Tasks_day_1.jl
@@ -0,0 +1,426 @@
+### A Pluto.jl notebook ###
+# v0.18.4
+
+using Markdown
+using InteractiveUtils
+
+# This Pluto notebook uses @bind for interactivity. When running this notebook outside of Pluto, the following 'mock version' of @bind gives bound variables a default value (instead of an error).
+macro bind(def, element)
+    quote
+        local iv = try Base.loaded_modules[Base.PkgId(Base.UUID("6e696c72-6542-2067-7265-42206c756150"), "AbstractPlutoDingetjes")].Bonds.initial_value catch; b -> missing; end
+        local el = $(esc(element))
+        global $(esc(def)) = Core.applicable(Base.get, el) ? Base.get(el) : iv(el)
+        el
+    end
+end
+
+# ╔═╡ a9cadc7e-10ce-4242-82af-2849b5f258f8
+# Oh, no, you found my secret! 😱
+# Don't change this hidden cell!
+begin
+	using PlutoUI
+	
+	function check_reverse_string()
+		if @isdefined reverse_string
+			test_str = "BlablaHahaOKLOL"
+			
+			try
+				if reverse_string(test_str) != reverse(test_str)
+					return md"""
+					🔴 Your function delivers wrong results 😢
+					"""
+				end
+			catch err
+				return md"""
+				🔴 Something is wrong with your function 😵
+				"""
+			end
+
+			return md"""
+			🟢 Nice, all is fine 👌
+			"""
+		else
+			return md"""
+			🔴 The function `reverse_string` is not implemented yet 🤨
+			"""
+		end
+	end
+	
+	function check_squaring_difference()
+		if @isdefined squaring_difference
+			random_numbers = (331, 236, 69, 738, 949, 631, 761, 119, 729, 280)
+			results_to_random_numbers = (3006919850, 777687850, 5720330, 74226126612, 202912760050, 39674819100, 83918590100, 50410780, 70671821220, 1540279020)
+		
+			for i in 1:length(random_numbers)
+				try
+					if squaring_difference(random_numbers[i]) != results_to_random_numbers[i]
+						return md"""
+						🔴 Your function delivers wrong results 😢
+						"""
+					end
+				catch err
+					return md"""
+					🔴 Something is wrong with your function 😵
+					"""
+				end
+			end
+
+			return md"""
+			🟢 Nice, all is fine 👌
+			"""
+		else
+			return md"""
+			🔴 The function `squaring_difference` is not implemented yet 🤨
+			"""
+		end
+	end
+	
+	md""
+end
+
+# ╔═╡ 094a714e-7a97-411b-8317-4d4acefaedbd
+md"""
+# BMI
+
+The BMI is calculated with this formula:
+
+$\text{BMI} = \frac{m}{l^2}$
+
+with $m$ as the mass in kg and $l$ as the height in m.
+
+Write code that shows "Underweight" for $\text{BMI} < 18.5$, "Normal weight" for $18.5 \le \text{BMI} < 25$ and "Overweight" for $25.0 \le \text{BMI}$.
+
+Test your code with the two sliders below.
+
+The variables `m` and `l` are already defined and their values are updated with the sliders.
+"""
+
+# ╔═╡ 1a43924b-da29-4154-bee4-c1fa65df6e40
+@bind m Slider(2:200)
+
+# ╔═╡ c22161f9-4def-4170-974f-86f2748037dc
+md"""
+`m` = $m (kg)
+"""
+
+# ╔═╡ f9e3b4af-bf21-4207-9061-3a91ae40c374
+@bind l Slider(0.30:0.01:2.50)
+
+# ╔═╡ 5781fdc3-54ed-4499-bf3d-c3438c85d1ef
+md"""
+`l` = $l (m)
+"""
+
+# ╔═╡ d286051e-c17e-41df-b8e3-e186b36d60cf
+# Your code starts here
+
+
+# ╔═╡ 9d69637b-2733-46f8-8423-41331aa45c28
+md"""
+# Number of grains
+
+You know for sure about the story with grains for every chess square.
+
+A chess board has 64 squares. For the first square, there is only one grain. For the second one, there are two grains. The number of grains doubles for every square.
+
+Calculate the number of grains for every square and their sum.
+"""
+
+# ╔═╡ 33ed17ca-2971-4de1-8bf7-03aa380fea57
+# Your code starts here
+
+
+# ╔═╡ f71b0085-8185-4d3f-b29e-90af6ac8957a
+md"""
+# Reverse string
+
+Write a function named `reverse_string` that takes an argument as a string and returns the reversed string.
+
+No cheating by using builtin reversing functions!
+
+Example: "string" would get "gnirts". 
+"""
+
+# ╔═╡ 2de65e70-661c-40c1-8fdb-03fd5b25b7e2
+# Write your function here
+
+
+# ╔═╡ d5bff992-e8b2-4f72-8943-db8ac4a671eb
+check_reverse_string()
+
+# ╔═╡ be22832f-2004-49ec-911c-96e7e790ba5a
+md"""
+# Squaring difference
+
+Write a function named `squaring_difference` that takes one argument `N` as a natural number and returns the following:
+
+$\left(\sum_{i=1}^N i\right)^2 - \sum_{i=1}^N i^2$
+"""
+
+# ╔═╡ 53b585dd-aa13-44c1-a3de-988e027ab0c4
+# Write your function here
+
+
+# ╔═╡ b08055c9-b6de-4495-9788-ff79928a85ef
+check_squaring_difference()
+
+# ╔═╡ b6fe803e-1300-4d00-97fa-de6646743f94
+md"""
+# XO game
+
+**Only for those who have time left and want to try a hard task!**
+
+Now that you know about matrices in Julia, use a matrix to present a XO board.
+
+To place a X or O, take the user input for the column and row using the function `readline`.
+
+Make sure you update the board after the user input.
+
+You want more?
+- Implement player names.
+- Implement a check if a user did win.
+- Check your code for possible performance issues. Try to minimize allocations.
+- Implement a playing AI. No, kidding! Just tell me to give you more tasks if get here 😂
+
+*BTW: You can use Julia for AI, so the programming language is not the limitation here* 😅
+"""
+
+# ╔═╡ 2c68b8a0-694b-4be0-9880-657d9ac1ef09
+# Your code starts here
+
+
+# ╔═╡ 00000000-0000-0000-0000-000000000001
+PLUTO_PROJECT_TOML_CONTENTS = """
+[deps]
+PlutoUI = "7f904dfe-b85e-4ff6-b463-dae2292396a8"
+
+[compat]
+PlutoUI = "~0.7.37"
+"""
+
+# ╔═╡ 00000000-0000-0000-0000-000000000002
+PLUTO_MANIFEST_TOML_CONTENTS = """
+# This file is machine-generated - editing it directly is not advised
+
+julia_version = "1.7.2"
+manifest_format = "2.0"
+
+[[deps.AbstractPlutoDingetjes]]
+deps = ["Pkg"]
+git-tree-sha1 = "8eaf9f1b4921132a4cff3f36a1d9ba923b14a481"
+uuid = "6e696c72-6542-2067-7265-42206c756150"
+version = "1.1.4"
+
+[[deps.ArgTools]]
+uuid = "0dad84c5-d112-42e6-8d28-ef12dabb789f"
+
+[[deps.Artifacts]]
+uuid = "56f22d72-fd6d-98f1-02f0-08ddc0907c33"
+
+[[deps.Base64]]
+uuid = "2a0f44e3-6c83-55bd-87e4-b1978d98bd5f"
+
+[[deps.ColorTypes]]
+deps = ["FixedPointNumbers", "Random"]
+git-tree-sha1 = "024fe24d83e4a5bf5fc80501a314ce0d1aa35597"
+uuid = "3da002f7-5984-5a60-b8a6-cbb66c0b333f"
+version = "0.11.0"
+
+[[deps.CompilerSupportLibraries_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "e66e0078-7015-5450-92f7-15fbd957f2ae"
+
+[[deps.Dates]]
+deps = ["Printf"]
+uuid = "ade2ca70-3891-5945-98fb-dc099432e06a"
+
+[[deps.Downloads]]
+deps = ["ArgTools", "LibCURL", "NetworkOptions"]
+uuid = "f43a241f-c20a-4ad4-852c-f6b1247861c6"
+
+[[deps.FixedPointNumbers]]
+deps = ["Statistics"]
+git-tree-sha1 = "335bfdceacc84c5cdf16aadc768aa5ddfc5383cc"
+uuid = "53c48c17-4a7d-5ca2-90c5-79b7896eea93"
+version = "0.8.4"
+
+[[deps.Hyperscript]]
+deps = ["Test"]
+git-tree-sha1 = "8d511d5b81240fc8e6802386302675bdf47737b9"
+uuid = "47d2ed2b-36de-50cf-bf87-49c2cf4b8b91"
+version = "0.0.4"
+
+[[deps.HypertextLiteral]]
+git-tree-sha1 = "2b078b5a615c6c0396c77810d92ee8c6f470d238"
+uuid = "ac1192a8-f4b3-4bfe-ba22-af5b92cd3ab2"
+version = "0.9.3"
+
+[[deps.IOCapture]]
+deps = ["Logging", "Random"]
+git-tree-sha1 = "f7be53659ab06ddc986428d3a9dcc95f6fa6705a"
+uuid = "b5f81e59-6552-4d32-b1f0-c071b021bf89"
+version = "0.2.2"
+
+[[deps.InteractiveUtils]]
+deps = ["Markdown"]
+uuid = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
+
+[[deps.JSON]]
+deps = ["Dates", "Mmap", "Parsers", "Unicode"]
+git-tree-sha1 = "3c837543ddb02250ef42f4738347454f95079d4e"
+uuid = "682c06a0-de6a-54ab-a142-c8b1cf79cde6"
+version = "0.21.3"
+
+[[deps.LibCURL]]
+deps = ["LibCURL_jll", "MozillaCACerts_jll"]
+uuid = "b27032c2-a3e7-50c8-80cd-2d36dbcbfd21"
+
+[[deps.LibCURL_jll]]
+deps = ["Artifacts", "LibSSH2_jll", "Libdl", "MbedTLS_jll", "Zlib_jll", "nghttp2_jll"]
+uuid = "deac9b47-8bc7-5906-a0fe-35ac56dc84c0"
+
+[[deps.LibGit2]]
+deps = ["Base64", "NetworkOptions", "Printf", "SHA"]
+uuid = "76f85450-5226-5b5a-8eaa-529ad045b433"
+
+[[deps.LibSSH2_jll]]
+deps = ["Artifacts", "Libdl", "MbedTLS_jll"]
+uuid = "29816b5a-b9ab-546f-933c-edad1886dfa8"
+
+[[deps.Libdl]]
+uuid = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
+
+[[deps.LinearAlgebra]]
+deps = ["Libdl", "libblastrampoline_jll"]
+uuid = "37e2e46d-f89d-539d-b4ee-838fcccc9c8e"
+
+[[deps.Logging]]
+uuid = "56ddb016-857b-54e1-b83d-db4d58db5568"
+
+[[deps.Markdown]]
+deps = ["Base64"]
+uuid = "d6f4376e-aef5-505a-96c1-9c027394607a"
+
+[[deps.MbedTLS_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "c8ffd9c3-330d-5841-b78e-0817d7145fa1"
+
+[[deps.Mmap]]
+uuid = "a63ad114-7e13-5084-954f-fe012c677804"
+
+[[deps.MozillaCACerts_jll]]
+uuid = "14a3606d-f60d-562e-9121-12d972cd8159"
+
+[[deps.NetworkOptions]]
+uuid = "ca575930-c2e3-43a9-ace4-1e988b2c1908"
+
+[[deps.OpenBLAS_jll]]
+deps = ["Artifacts", "CompilerSupportLibraries_jll", "Libdl"]
+uuid = "4536629a-c528-5b80-bd46-f80d51c5b363"
+
+[[deps.Parsers]]
+deps = ["Dates"]
+git-tree-sha1 = "85b5da0fa43588c75bb1ff986493443f821c70b7"
+uuid = "69de0a69-1ddd-5017-9359-2bf0b02dc9f0"
+version = "2.2.3"
+
+[[deps.Pkg]]
+deps = ["Artifacts", "Dates", "Downloads", "LibGit2", "Libdl", "Logging", "Markdown", "Printf", "REPL", "Random", "SHA", "Serialization", "TOML", "Tar", "UUIDs", "p7zip_jll"]
+uuid = "44cfe95a-1eb2-52ea-b672-e2afdf69b78f"
+
+[[deps.PlutoUI]]
+deps = ["AbstractPlutoDingetjes", "Base64", "ColorTypes", "Dates", "Hyperscript", "HypertextLiteral", "IOCapture", "InteractiveUtils", "JSON", "Logging", "Markdown", "Random", "Reexport", "UUIDs"]
+git-tree-sha1 = "bf0a1121af131d9974241ba53f601211e9303a9e"
+uuid = "7f904dfe-b85e-4ff6-b463-dae2292396a8"
+version = "0.7.37"
+
+[[deps.Printf]]
+deps = ["Unicode"]
+uuid = "de0858da-6303-5e67-8744-51eddeeeb8d7"
+
+[[deps.REPL]]
+deps = ["InteractiveUtils", "Markdown", "Sockets", "Unicode"]
+uuid = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
+
+[[deps.Random]]
+deps = ["SHA", "Serialization"]
+uuid = "9a3f8284-a2c9-5f02-9a11-845980a1fd5c"
+
+[[deps.Reexport]]
+git-tree-sha1 = "45e428421666073eab6f2da5c9d310d99bb12f9b"
+uuid = "189a3867-3050-52da-a836-e630ba90ab69"
+version = "1.2.2"
+
+[[deps.SHA]]
+uuid = "ea8e919c-243c-51af-8825-aaa63cd721ce"
+
+[[deps.Serialization]]
+uuid = "9e88b42a-f829-5b0c-bbe9-9e923198166b"
+
+[[deps.Sockets]]
+uuid = "6462fe0b-24de-5631-8697-dd941f90decc"
+
+[[deps.SparseArrays]]
+deps = ["LinearAlgebra", "Random"]
+uuid = "2f01184e-e22b-5df5-ae63-d93ebab69eaf"
+
+[[deps.Statistics]]
+deps = ["LinearAlgebra", "SparseArrays"]
+uuid = "10745b16-79ce-11e8-11f9-7d13ad32a3b2"
+
+[[deps.TOML]]
+deps = ["Dates"]
+uuid = "fa267f1f-6049-4f14-aa54-33bafae1ed76"
+
+[[deps.Tar]]
+deps = ["ArgTools", "SHA"]
+uuid = "a4e569a6-e804-4fa4-b0f3-eef7a1d5b13e"
+
+[[deps.Test]]
+deps = ["InteractiveUtils", "Logging", "Random", "Serialization"]
+uuid = "8dfed614-e22c-5e08-85e1-65c5234f0b40"
+
+[[deps.UUIDs]]
+deps = ["Random", "SHA"]
+uuid = "cf7118a7-6976-5b1a-9a39-7adc72f591a4"
+
+[[deps.Unicode]]
+uuid = "4ec0a83e-493e-50e2-b9ac-8f72acf5a8f5"
+
+[[deps.Zlib_jll]]
+deps = ["Libdl"]
+uuid = "83775a58-1f1d-513f-b197-d71354ab007a"
+
+[[deps.libblastrampoline_jll]]
+deps = ["Artifacts", "Libdl", "OpenBLAS_jll"]
+uuid = "8e850b90-86db-534c-a0d3-1478176c7d93"
+
+[[deps.nghttp2_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "8e850ede-7688-5339-a07c-302acd2aaf8d"
+
+[[deps.p7zip_jll]]
+deps = ["Artifacts", "Libdl"]
+uuid = "3f19e933-33d8-53b3-aaab-bd5110c3b7a0"
+"""
+
+# ╔═╡ Cell order:
+# ╟─094a714e-7a97-411b-8317-4d4acefaedbd
+# ╟─1a43924b-da29-4154-bee4-c1fa65df6e40
+# ╟─c22161f9-4def-4170-974f-86f2748037dc
+# ╟─f9e3b4af-bf21-4207-9061-3a91ae40c374
+# ╟─5781fdc3-54ed-4499-bf3d-c3438c85d1ef
+# ╠═d286051e-c17e-41df-b8e3-e186b36d60cf
+# ╟─9d69637b-2733-46f8-8423-41331aa45c28
+# ╠═33ed17ca-2971-4de1-8bf7-03aa380fea57
+# ╟─f71b0085-8185-4d3f-b29e-90af6ac8957a
+# ╠═2de65e70-661c-40c1-8fdb-03fd5b25b7e2
+# ╟─d5bff992-e8b2-4f72-8943-db8ac4a671eb
+# ╟─be22832f-2004-49ec-911c-96e7e790ba5a
+# ╠═53b585dd-aa13-44c1-a3de-988e027ab0c4
+# ╟─b08055c9-b6de-4495-9788-ff79928a85ef
+# ╟─b6fe803e-1300-4d00-97fa-de6646743f94
+# ╠═2c68b8a0-694b-4be0-9880-657d9ac1ef09
+# ╟─a9cadc7e-10ce-4242-82af-2849b5f258f8
+# ╟─00000000-0000-0000-0000-000000000001
+# ╟─00000000-0000-0000-0000-000000000002