diff --git a/numerical_methods/durand_kerner_roots.c b/numerical_methods/durand_kerner_roots.c
index de79e448..6d7735a8 100644
--- a/numerical_methods/durand_kerner_roots.c
+++ b/numerical_methods/durand_kerner_roots.c
@@ -187,7 +187,7 @@ int main(int argc, char **argv)
     }
 end:
 
-    dtime = end_timer(timer);
+    dtime = end_timer_delete(timer);
 
 #if defined(DEBUG) || !defined(NDEBUG)
     fclose(log_file);
diff --git a/numerical_methods/qr_decomposition.c b/numerical_methods/qr_decomposition.c
index 1c28b178..a4fd58fb 100644
--- a/numerical_methods/qr_decomposition.c
+++ b/numerical_methods/qr_decomposition.c
@@ -140,7 +140,7 @@ int main(void)
     function_timer *t1 = new_timer();
     start_timer(t1);
     qr_decompose(A, Q, R, ROWS, COLUMNS);
-    double dtime = end_timer(t1);
+    double dtime = end_timer_delete(t1);
 
     print_2d(R, ROWS, COLUMNS);
     print_2d(Q, ROWS, COLUMNS);
diff --git a/numerical_methods/qr_eigen_values.c b/numerical_methods/qr_eigen_values.c
index 9b34219a..5ed19c91 100644
--- a/numerical_methods/qr_eigen_values.c
+++ b/numerical_methods/qr_eigen_values.c
@@ -202,7 +202,7 @@ int main(int argc, char **argv)
         columns--;
     }
     eigen_vals[0] = A[0][0];
-    double dtime = end_timer(t1);
+    double dtime = end_timer_delete(t1);
 
 #if defined(DEBUG) || !defined(NDEBUG)
     print_matrix(R, mat_size, mat_size);