diff --git a/DeitelC/Chapter4/PrimeNums.c b/DeitelC/Chapter4/PrimeNums.c
new file mode 100644
index 0000000..eaf61ec
--- /dev/null
+++ b/DeitelC/Chapter4/PrimeNums.c
@@ -0,0 +1,21 @@
+#include <stdio.h>
+
+int main(void) {
+    puts("Show all prime numbers until: ");
+    int i;
+    if(scanf("%d", &i) != 1 || i < 2) {
+    puts("ERROR, entered integer NOT valid!");
+    }
+
+    for(int y = 2; y < i; y++) {
+    int counter = 0;
+        for(int a = 2; a < y; a++) {
+            if(y % a == 0) {
+                counter = 1;
+            }
+        }
+    if (!counter) {
+        printf("%d\t", y);
+    }
+    }
+}
diff --git a/DeitelC/Chapter4/a.out b/DeitelC/Chapter4/a.out
index db8e620..d707f01 100644
Binary files a/DeitelC/Chapter4/a.out and b/DeitelC/Chapter4/a.out differ
diff --git a/DeitelC/Chapter4/example4-3.c b/DeitelC/Chapter4/example4-3.c
new file mode 100644
index 0000000..13bd5e1
--- /dev/null
+++ b/DeitelC/Chapter4/example4-3.c
@@ -0,0 +1,33 @@
+#include <stdio.h>
+#include <math.h>
+
+int main(void){
+    int sum = 0;
+    for(int i = 1; i <= 99; i += 2) {
+        sum += i;
+}
+
+printf("%s%d\n","Sum of 1-99 odd numbers: ", sum);
+
+printf("%-15.1f\n", 333.546372);
+printf("%-15.2f\n", 333.546372);
+printf("%-15.3f\n", 333.546372);
+printf("%-15.4f\n", 333.546372);
+printf("%-15.5f\n", 333.546372);
+printf("%10.2f\n", pow(2.5,3));
+
+int counter = 1;
+
+while (counter <= 20) {
+    if(counter % 5 == 0) {
+    printf("%d\n", counter);
+    } else {
+        printf("%d\t", counter);
+    }
+
+    ++counter;
+}
+
+
+return 0;
+}
diff --git a/DeitelC/Chapter4/example4-7.c b/DeitelC/Chapter4/example4-7.c
new file mode 100644
index 0000000..d801f54
--- /dev/null
+++ b/DeitelC/Chapter4/example4-7.c
@@ -0,0 +1,22 @@
+#include <stdio.h>
+
+int main(void) {
+    for(int x = 1; x <= 13; x += 2) {
+        printf("%d\t",x);
+    }
+    puts("");
+    for(int x = 2; x <= 17; x += 3) {
+        printf("%d\t",x);
+    }
+    puts("");
+    for(int x = 30; x >= -30; x -= 10) {
+        printf("%d\t",x);
+    }
+    puts("");
+    for(int x = 15; x <= 55; x += 8) {
+        printf("%d\t",x);
+    }
+    puts("");
+
+    return 0;
+}
diff --git a/DeitelC/Chapter4/example4-8.c b/DeitelC/Chapter4/example4-8.c
new file mode 100644
index 0000000..3d5e7e8
--- /dev/null
+++ b/DeitelC/Chapter4/example4-8.c
@@ -0,0 +1,15 @@
+#include <stdio.h>
+int main()
+ {
+int x, i, j;
+printf("%s", "Enter an integer in the range 1-20:"); 
+scanf("%d", &x); // read values for x
+ for (i = 1; i <= x; i++) {
+for (j = 1; j <= x; j++) { 
+if (j==i)
+ printf("%c",'@'); // output @ 12 
+    else
+ printf(" "); } // end inner for 15 
+printf("\n");
+ } // end outer for 17 
+} // end of main
diff --git a/DeitelC/Chapter4/sumAndAverage.c b/DeitelC/Chapter4/sumAndAverage.c
new file mode 100644
index 0000000..9541de2
--- /dev/null
+++ b/DeitelC/Chapter4/sumAndAverage.c
@@ -0,0 +1,17 @@
+#include <stdio.h>
+
+int main(void) {
+    int x = 0, counter = 0;
+    scanf("%d", &x);
+
+    for(int t = 0; t < x; t++){
+        int i;
+        scanf("%d", &i);
+        counter += i;
+    }
+
+ printf("%d\n", counter/x);
+
+return 0;
+}
+