diff --git a/qualdev/TD-Debug.ts b/qualdev/TD-Debug.ts
index 2c5a5b07809a11b5b0e6dd04d8c927502a4405e6..24a429b41ec92531966e63ed872e7d023322a7de 100644
--- a/qualdev/TD-Debug.ts
+++ b/qualdev/TD-Debug.ts
@@ -88,3 +88,47 @@ let tab22 = [...tab12];
 tab12[1] = 5;
 
 console.log(tab12, tab22); 
+
+
+//exo 7 : multiplication via addition
+
+
+deb7(5, 3);
+
+function deb7(x: number, y: number): number {
+  let val = 0;
+
+  for (let i = 0; i < y; i++) {
+    val += x;
+  }
+
+  return val;
+}
+
+
+function multiplicationParAddition(x: number, y: number): number {
+    let val = 0;
+  
+    if (y > 0) {
+      for (let i = 0; i < y; i++) {
+        val += x;
+      }
+    } else {
+      for (let i = 0; i > y; i--) {
+        val -= x;
+      }
+    }
+  
+    return val;
+  }
+  
+
+  let couples = [
+    [0, 0], [5, 3], [3, 5], [-5, -2], [-2, -5],
+    [-74, 2], [-1, 75], [10, -25], [10, -3]
+  ];
+  
+  for (let [x, y] of couples) {
+    console.log(`multiplicationParAddition(${x}, ${y}) = ${multiplicationParAddition(x, y)}`);
+  }
+  
\ No newline at end of file