diff --git a/CHANGELOG.md b/CHANGELOG.md
index 018db67..ac20cf1 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -13,6 +13,12 @@ All notable changes to this project will be documented in this file.
 - Add BitmaskLib.sol
 - *(Mask)* Add Mask custom type and its library
 - *(BitmaskLib)* Implement updateDataWith
+- Add ArithmeticLib library
+- *(SignedInt)* Add custom type
+- *(UnsignedInt)* Add custom type
+- *(UnsignedInt)* Add UnsignedLib
+- *(ArithmeticLib)* Add functions
+- *(SignedInt)* Add functions
 
 ### 🐛 Bug Fixes
 
@@ -27,6 +33,7 @@ All notable changes to this project will be documented in this file.
 - *(BitmaskLib)* Update Mask custom type
 - *(BitmaskLib)* Update `build` function params
 - *(BitmaskLib)* Remove `getLength` function
+- *(UnsignedInt)* Update functions
 
 ### 📚 Documentation
 
@@ -35,6 +42,7 @@ All notable changes to this project will be documented in this file.
 
 ### 🎨 Styling
 
+- *(SlotLib)* Update setUp function
 - Move Mask to BitmaskLib
 - *(BitmaskLib)* Rename updateDataWith as updateLeftPadded
 - Format BitmaskLib.t.sol
@@ -56,5 +64,7 @@ All notable changes to this project will be documented in this file.
 - Remove redundant contracts
 - Update Gasgnome.sol
 - Add CHANGELOG.md
+- Update CHANGELOG.md
+- Update Gasgnome.sol
 
 <!-- generated by git-cliff -->
diff --git a/src/Gasgnome.sol b/src/Gasgnome.sol
index 2fe941a..932e554 100644
--- a/src/Gasgnome.sol
+++ b/src/Gasgnome.sol
@@ -1,8 +1,15 @@
 // SPDX-License-Identifier: UNLICENSED
 pragma solidity 0.8.26;
 
-import "./libraries/StorageLib.sol";
+/// @notice Libraries
+import "./libraries/ArithmeticLib.sol";
 import "./libraries/BitmaskLib.sol";
+import "./libraries/StorageLib.sol";
+
+/// @notice Types
+import "./types/SignedInt.sol";
+import "./types/Slot.sol";
+import "./types/UnsignedInt.sol";
 
 library Gasgnome {
     string internal constant AUTHOR = "https://github.com/icanvardar";
diff --git a/src/libraries/ArithmeticLib.sol b/src/libraries/ArithmeticLib.sol
new file mode 100644
index 0000000..1215b7c
--- /dev/null
+++ b/src/libraries/ArithmeticLib.sol
@@ -0,0 +1,36 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.8.26;
+
+library ArithmeticLib {
+    function convertWithSize(bytes32 b, uint16 sizeInBytes, uint8 sizeInBits) public pure returns (bytes32 to) {
+        assembly {
+            /// TODO: add custom error here - sizeInBytes cannot be zero/cannot be bigger than 256 bits
+            if or(eq(sizeInBytes, 0), gt(sizeInBytes, 0x100)) { revert(0x00, 0x00) }
+
+            /// TODO: add custom error here - sizeInBytes has to be multiple of eight
+            if gt(mod(sizeInBytes, 0x8), 0) { revert(0x00, 0x00) }
+        }
+
+        uint8 sizeCap = cap(sizeInBits);
+
+        assembly {
+            /// TODO: add custom error here - size cap cannot be bigger than given size in bytes
+            if gt(sizeCap, sizeInBytes) { revert(0x00, 0x00) }
+
+            to := b
+        }
+    }
+
+    /// NOTE: finds the nearest bit cap in multiple of eight
+    function cap(uint8 bitSize) public pure returns (uint8 res) {
+        assembly {
+            for { let i := 0x0 } lt(i, 0x21) { i := add(i, 1) } {
+                let tmp := mul(add(i, 1), 8)
+                if or(gt(tmp, bitSize), eq(tmp, bitSize)) {
+                    res := tmp
+                    break
+                }
+            }
+        }
+    }
+}
diff --git a/src/types/SignedInt.sol b/src/types/SignedInt.sol
new file mode 100644
index 0000000..49c52f8
--- /dev/null
+++ b/src/types/SignedInt.sol
@@ -0,0 +1,98 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.8.26;
+
+import { ArithmeticLib } from "../libraries/ArithmeticLib.sol";
+
+type SignedInt is bytes32;
+
+using {
+    addSignedInt as +,
+    subSignedInt as -,
+    mulSignedInt as *,
+    divSignedInt as /,
+    modSignedInt as %,
+    expSignedInt as ^
+} for SignedInt global;
+
+function addSignedInt(SignedInt left, SignedInt right) pure returns (SignedInt res) {
+    assembly {
+        res := add(left, right)
+    }
+}
+
+function subSignedInt(SignedInt left, SignedInt right) pure returns (SignedInt res) {
+    assembly {
+        res := sub(left, right)
+    }
+}
+
+function mulSignedInt(SignedInt left, SignedInt right) pure returns (SignedInt res) {
+    assembly {
+        switch or(iszero(left), iszero(right))
+        case 0 { res := 0 }
+        case 1 { res := mul(left, right) }
+    }
+}
+
+function divSignedInt(SignedInt left, SignedInt right) pure returns (SignedInt res) {
+    assembly {
+        res := div(left, right)
+    }
+}
+
+function modSignedInt(SignedInt left, SignedInt right) pure returns (SignedInt res) {
+    assembly {
+        if iszero(right) {
+            /// TODO: add custom error here - modulo by zero check
+            revert(0x00, 0x00)
+        }
+
+        res := mod(left, right)
+    }
+}
+
+function expSignedInt(SignedInt left, SignedInt right) pure returns (SignedInt res) {
+    assembly {
+        res := exp(left, right)
+    }
+}
+
+using SignedIntLib for SignedInt global;
+
+library SignedIntLib {
+    function convertWithSize(SignedInt u, uint16 sizeInBytes) public pure returns (int256 to) {
+        bytes32 result = ArithmeticLib.convertWithSize(SignedInt.unwrap(u), sizeInBytes, sizeInBits(u));
+
+        assembly {
+            to := result
+        }
+    }
+
+    function sizeInBits(SignedInt s) public pure returns (uint8 size) {
+        assembly {
+            let tmp
+            let isNegative := sgt(0, s)
+            let absValue := s
+            if isNegative { absValue := sub(0, s) }
+
+            for { let i := 0x1f } gt(i, 0x0) { i := sub(i, 1) } {
+                let b := byte(i, absValue)
+
+                /// Check existency of first nibble
+                let x := and(b, 0x0f)
+                if gt(x, 0) {
+                    size := add(size, add(tmp, 0x1))
+                    tmp := 0x0
+                }
+                if eq(x, 0) { tmp := add(tmp, 0x1) }
+
+                /// Check existency of second nibble
+                let y := and(b, 0xf0)
+                if gt(y, 0) { size := add(size, 0x1) }
+                if eq(y, 0) { tmp := add(tmp, 0x1) }
+            }
+
+            size := mul(size, 0x4)
+        }
+    }
+}
diff --git a/src/types/UnsignedInt.sol b/src/types/UnsignedInt.sol
new file mode 100644
index 0000000..1a8305a
--- /dev/null
+++ b/src/types/UnsignedInt.sol
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.8.26;
+
+import { ArithmeticLib } from "../libraries/ArithmeticLib.sol";
+
+type UnsignedInt is bytes32;
+
+using {
+    addUnsignedInt as +,
+    subUnsignedInt as -,
+    mulUnsignedInt as *,
+    divUnsignedInt as /,
+    modUnsignedInt as %,
+    expUnsignedInt as ^
+} for UnsignedInt global;
+
+function addUnsignedInt(UnsignedInt left, UnsignedInt right) pure returns (UnsignedInt res) {
+    assembly {
+        res := add(left, right)
+
+        if lt(res, left) {
+            /// TODO: add custom error here - overflow check
+            revert(0x00, 0x00)
+        }
+    }
+}
+
+function subUnsignedInt(UnsignedInt left, UnsignedInt right) pure returns (UnsignedInt res) {
+    assembly {
+        if gt(right, left) {
+            /// TODO: add custom error here - underflow check
+            revert(0x00, 0x00)
+        }
+
+        res := sub(left, right)
+    }
+}
+
+function mulUnsignedInt(UnsignedInt left, UnsignedInt right) pure returns (UnsignedInt res) {
+    assembly {
+        switch or(iszero(left), iszero(right))
+        case 0 { res := 0 }
+        case 1 { res := mul(left, right) }
+    }
+}
+
+function divUnsignedInt(UnsignedInt left, UnsignedInt right) pure returns (UnsignedInt res) {
+    assembly {
+        if eq(right, 0) {
+            /// TODO: add custom error here - division by zero check
+            revert(0x00, 0x00)
+        }
+
+        res := div(left, right)
+    }
+}
+
+function modUnsignedInt(UnsignedInt left, UnsignedInt right) pure returns (UnsignedInt res) {
+    assembly {
+        if iszero(right) {
+            /// TODO: add custom error here - modulo by zero check
+            revert(0x00, 0x00)
+        }
+
+        res := mod(left, right)
+    }
+}
+
+function expUnsignedInt(UnsignedInt left, UnsignedInt right) pure returns (UnsignedInt res) {
+    assembly {
+        res := exp(left, right)
+    }
+}
+
+using UnsignedIntLib for UnsignedInt global;
+
+library UnsignedIntLib {
+    function convertWithSize(UnsignedInt u, uint16 sizeInBytes) public pure returns (uint256 to) {
+        bytes32 result = ArithmeticLib.convertWithSize(UnsignedInt.unwrap(u), sizeInBytes, sizeInBits(u));
+
+        assembly {
+            to := result
+        }
+    }
+
+    function sizeInBits(UnsignedInt u) public pure returns (uint8 size) {
+        assembly {
+            let tmp
+            for { let i := 0x1f } gt(i, 0x0) { i := sub(i, 1) } {
+                let b := byte(i, u)
+
+                /// NOTE: check existency of first nibble
+                let x := and(b, 0x0f)
+                if gt(x, 0) {
+                    size := add(size, add(tmp, 0x1))
+                    tmp := 0x0
+                }
+                if eq(x, 0) { tmp := add(tmp, 0x1) }
+
+                /// NOTE: check existency of second nibble
+                let y := and(b, 0xf0)
+                if gt(y, 0) { size := add(size, 0x1) }
+                if eq(y, 0) { tmp := add(tmp, 0x1) }
+            }
+
+            size := mul(size, 0x4)
+        }
+    }
+}
diff --git a/test/ArithmeticLib.t.sol b/test/ArithmeticLib.t.sol
new file mode 100644
index 0000000..b7d9021
--- /dev/null
+++ b/test/ArithmeticLib.t.sol
@@ -0,0 +1,7 @@
+// SPDX-License-Identifier: UNLICENSED
+pragma solidity 0.8.26;
+
+import { ArithmeticLib } from "../src/libraries/ArithmeticLib.sol";
+import { Test, console } from "forge-std/Test.sol";
+
+contract ArithmeticLibTest is Test { }