diff --git a/cairo_program/src/bool.cairo b/cairo_program/src/bool.cairo
index cafad1e..e8d4f47 100644
--- a/cairo_program/src/bool.cairo
+++ b/cairo_program/src/bool.cairo
@@ -18,7 +18,6 @@ fn is_adult(x: u8) -> bool {
     return true;
 }
 
-
 // determine even numbers
 fn is_even(x: u8) -> bool {
     if x % 2 == 0 {
diff --git a/cairo_program/src/integer.cairo b/cairo_program/src/integer.cairo
index 9501eca..36555f2 100644
--- a/cairo_program/src/integer.cairo
+++ b/cairo_program/src/integer.cairo
@@ -1,20 +1,53 @@
+use core::num::traits::OverflowingMul;
+
 #[executable]
 fn main() {
-    let result: u8 = add_num(5, 6);
-    println!("the sum of x & y is: {}", result);
-    assert(result == 11, 'invalid sum logic');
+    let add_result: u8 = add_num(5, 6);
+    println!("the sum of x & y is: {}", add_result);
+    assert(add_result == 11, 'invalid sum logic');
 
     let sub_result: u8 = sub_num(10, 5);
     println!("sub result is: {}", sub_result);
     assert(sub_result == 5, 'invalid sub logic');
+
+        // Test subtraction that should panic (10 - 15 = negative)
+    // sub_num(10, 15); // This would panic
+
+    let mul_result: u8 = mul_num(255, 1);
+    println!("mul result is: {}", mul_result);
+    assert(mul_result == 255, 'invalid mul logic');
+
+    let div_result: u8 = div_num(20, 0);
+    println!("div result is: {}", div_result);
+    assert(div_result == 5, 'invalid div logic');
+
+    // Test division by zero - should panic
+    // div_num(10, 0); // This would panic
 }
 
 // addition logic
 fn add_num(x: u8, y: u8) -> u8 {
-    x + y
+    return x + y;
 }
 
 // subtraction logic
 fn sub_num(x: u8, y: u8) -> u8 {
-    return x - y;
+    assert!(!(y > x), "negative result not allowed");
+    x - y
+}
+
+// multiplication logic
+fn mul_num(x: u8, y: u8) -> u8 {
+    let (result_, overflowed_) = x.overflowing_mul(y);
+
+    assert!(!(overflowed_), "multiplication overflowed");
+
+    result_
 }
+
+// division logic with division by zero check
+fn div_num(x: u8, y: u8) -> u8 {
+    assert!(!(y == 0), "Cannot be Zero");
+    x / y
+}
+
diff --git a/cairo_program/src/lib.cairo b/cairo_program/src/lib.cairo
index acc7644..b1c3620 100644
--- a/cairo_program/src/lib.cairo
+++ b/cairo_program/src/lib.cairo
@@ -1,5 +1,5 @@
 // mod hello_world;
 // mod short_string;
-// mod integer;
+mod integer;
 // mod bool;
-mod bytearray;
\ No newline at end of file
+// mod bytearray;
\ No newline at end of file
diff --git a/starknet_contracts/Scarb.toml b/starknet_contracts/Scarb.toml
index 29cf20f..b24c100 100644
--- a/starknet_contracts/Scarb.toml
+++ b/starknet_contracts/Scarb.toml
@@ -5,8 +5,13 @@ edition = "2024_07"
 
 # See more keys and their definitions at https://docs.swmansion.com/scarb/docs/reference/manifest.html
 
+
 [dependencies]
 starknet = "2.18.0"
+cairo_execute = "2.18.0"
+
+[cairo]
+enable-gas = true
 
 [dev-dependencies]
 snforge_std = "0.56.0"
diff --git a/starknet_contracts/src/arithmetic.cairo b/starknet_contracts/src/arithmetic.cairo
new file mode 100644
index 0000000..939782b
--- /dev/null
+++ b/starknet_contracts/src/arithmetic.cairo
@@ -0,0 +1,28 @@
+use core::num::traits::OverflowingMul;
+
+// addition logic
+pub fn add_num(x: u32, y: u32) -> u32 {
+    return x + y;
+}
+
+// subtraction logic
+fn sub_num(x: u8, y: u8) -> u8 {
+    assert!(!(y > x), "negative result not allowed");
+    x - y
+}
+
+// multiplication logic
+fn mul_num(x: u8, y: u8) -> u8 {
+    let (result_, overflowed_) = x.overflowing_mul(y);
+
+    assert!(!(overflowed_), "multiplication overflowed");
+
+    result_
+}
+
+// division logic with division by zero check
+fn div_num(x: u8, y: u8) -> u8 {
+    assert!(!(y == 0), "Cannot be Zero");
+    x / y
+}
+
diff --git a/starknet_contracts/src/lib.cairo b/starknet_contracts/src/lib.cairo
index f1b82bb..02257ad 100644
--- a/starknet_contracts/src/lib.cairo
+++ b/starknet_contracts/src/lib.cairo
@@ -1,5 +1,7 @@
 /// Interface representing `HelloContract`.
 /// This interface allows modification and retrieval of the contract's storage count.
+
+mod arithmetic;
 #[starknet::interface]
 pub trait ICounter<T> {
     /// Increase count.
@@ -10,21 +12,48 @@ pub trait ICounter<T> {
 
 /// Simple contract for managing count.
 #[starknet::contract]
-mod Counter {
+pub mod Counter {
     use starknet::storage::{StoragePointerReadAccess, StoragePointerWriteAccess};
+    use starknet::{ContractAddress, get_caller_address};
+    use super::arithmetic::{add_num};
 
     #[storage]
     struct Storage {
         count: u32,
+        owner: ContractAddress,    
+    }
+
+    #[constructor]
+    fn constructor(ref self: ContractState, owner: ContractAddress) {
+        self.owner.write(owner); // no .into() needed    }
+    }
+
+    #[generate_trait]
+    impl PrivateImpl of PrivateTrait {
+        fn assert_only_owner(self: @ContractState ) {
+            assert(get_caller_address() == self.owner.read(), 'Caller not the Owner');
+        }
     }
+   
+
 
     #[abi(embed_v0)]
     impl CounterImpl of super::ICounter<ContractState> {
         fn increase_count(ref self: ContractState, amount: u32) {
+
+            // Only owner 
+            self.assert_only_owner();
             assert(amount != 0, 'Amount cannot be 0');
-            self.count.write(self.count.read() + amount);
+
+            // Read current count and add the amount
+            let current_count = self.count.read();
+            let new_count = add_num(current_count, amount);
+            self.count.write(new_count);
+
+            assert(new_count == current_count + amount, 'Count increase failed');
         }
 
+
         fn get_count(self: @ContractState) -> u32 {
             self.count.read()
         }