diff --git a/pset5/3-qualify.c b/pset5/3-qualify.c
new file mode 100644
index 0000000..5f8eec3
--- /dev/null
+++ b/pset5/3-qualify.c
@@ -0,0 +1,38 @@
+#include <stdio.h>
+
+// Function prototypes
+int get_sum(int n);
+
+int main(void) {
+  // Initialize variables
+  int n, m;
+  scanf("%i%i", &n, &m);
+
+  // Brute force answer
+  for (int i = 1; i < n; i++) {
+    if (i / m == get_sum(i)) {
+      printf("%i\n", i);
+    }
+  }
+
+  return 0;
+}
+
+int get_sum(int n) {
+  // Tabulate nums
+  int length = 0;
+  int nums[6];
+  int tmp = n;
+  while (tmp > 0) {
+    nums[length] = tmp % 10;
+    tmp /= 10;
+    length++;
+  }
+
+  // Calculate sum
+  int sum = 0;
+  for (int i = 0; i < length; i++) {
+    sum += nums[i] * nums[i];
+  }
+	return sum;
+}
diff --git a/pset5/4-isomorph.c b/pset5/4-isomorph.c
new file mode 100644
index 0000000..506038d
--- /dev/null
+++ b/pset5/4-isomorph.c
@@ -0,0 +1,56 @@
+#include <stdio.h>
+
+// Function prototypes
+int test(int n);
+void tabulate(int *num, int n);
+
+int main(void) {
+  // Initialize variables
+  int n;
+  scanf("%d", &n);
+
+  // Determine if it is a isomorph
+  if (n > 0 && n <= 10000) {
+    if (test(n)) {
+      printf("Yes\n");
+    } else {
+      printf("No\n");
+    }
+  } else {
+    printf("%i out of range\n", n);
+  }
+
+  return 0;
+}
+
+int test(int n) {
+  int pow = n * n;
+  int num1[6], num2[12];
+
+  // Get the length of n
+  int length = 0;
+  int tmp = n;
+  while (tmp > 0) {
+    tmp /= 10;
+    length++;
+  }
+
+  // Tabulate them
+  tabulate(&num1[0], n); // Or: num1
+  tabulate(&num2[0], pow);
+
+  for (int i = 0; i < length; i++) {
+    if (num1[i] != num2[i]) {
+      return 0; // False
+    }
+  }
+  return 1; // True
+}
+
+void tabulate(int *num, int n) {
+  while (n > 0) {
+    *num = n % 10;
+    n /= 10;
+    num++;
+  }
+}
diff --git a/pset5/5-matrix.c b/pset5/5-matrix.c
new file mode 100644
index 0000000..ab261f6
--- /dev/null
+++ b/pset5/5-matrix.c
@@ -0,0 +1,32 @@
+#include <math.h>
+#include <stdio.h>
+
+// Function prototypes
+int checkf(float f);
+
+int main(void) {
+  // Initialize variables
+  float m, n;
+  scanf("%f%f", &m, &n);
+
+  int a;
+  float bf, cf;
+  for (a = 0; a <= (int)m; a++) {
+    cf = (float)a + (n / 2) - (m *  2);
+    if (checkf(cf) == 1) {
+      bf = ((n / 2) - m - cf * 2);
+      if (checkf(bf) == 1) {
+        printf("%i %i %i\n", a, (int)bf, (int)cf);
+      }
+    }
+  }
+  return 0;
+}
+
+int checkf(float f) {
+  if (floorf(f) == f && f >= 0) {
+    return 1; // True
+  } else {
+    return 0; // False
+  }
+}