diff --git a/【实践课内】4.循环结构1/7-1 求奇数和.c b/【实践课内】4.循环结构1/7-1 求奇数和.c
new file mode 100644
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--- /dev/null
+++ b/【实践课内】4.循环结构1/7-1 求奇数和.c	
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main() {
+    int x, ans = 0;
+
+    while (scanf("%d", &x), x > 0) {
+        if (x % 2 == 1) {
+            ans += x;
+        }
+    }
+
+    printf("%d\n", ans);
+
+    return 0;
+}
diff --git a/【实践课内】4.循环结构1/7-1 求奇数和.jpg b/【实践课内】4.循环结构1/7-1 求奇数和.jpg
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diff --git a/【实践课内】4.循环结构1/7-2 100以内的加法.c b/【实践课内】4.循环结构1/7-2 100以内的加法.c
new file mode 100644
index 0000000..68baa2c
--- /dev/null
+++ b/【实践课内】4.循环结构1/7-2 100以内的加法.c	
@@ -0,0 +1,15 @@
+#include <stdio.h>
+
+int main() {
+    int m, n, ans = 0;
+
+    scanf("%d%d", &m, &n);
+
+    for (int i = m; i <= n; i++) {
+        ans += i;
+    }
+
+    printf("%d\n", ans);
+
+    return 0;
+}
diff --git a/【实践课内】4.循环结构1/7-2 100以内的加法.jpg b/【实践课内】4.循环结构1/7-2 100以内的加法.jpg
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diff --git a/【实践课内】4.循环结构1/7-3 统计学生平均成绩与及格人数.c b/【实践课内】4.循环结构1/7-3 统计学生平均成绩与及格人数.c
new file mode 100644
index 0000000..47768a5
--- /dev/null
+++ b/【实践课内】4.循环结构1/7-3 统计学生平均成绩与及格人数.c	
@@ -0,0 +1,27 @@
+#include <stdio.h>
+
+int main() {
+    int n, count = 0, sum_score = 0;
+
+    scanf("%d", &n);
+
+    if (n == 0) {
+        printf("average = 0.0\ncount = 0\n");
+    } else {
+        for (int i = 1; i <= n; i++) {
+            int score;
+
+            scanf("%d", &score);
+
+            sum_score += score;
+
+            if (score >= 60) {
+                count++;
+            }
+        }
+
+        printf("average = %.1lf\ncount = %d\n", (double)sum_score / n, count);
+    }
+
+    return 0;
+}
diff --git a/【实践课内】4.循环结构1/7-3 统计学生平均成绩与及格人数.jpg b/【实践课内】4.循环结构1/7-3 统计学生平均成绩与及格人数.jpg
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diff --git a/【实践课内】4.循环结构1/7-4 循环-4 的倍数.c b/【实践课内】4.循环结构1/7-4 循环-4 的倍数.c
new file mode 100644
index 0000000..1c5709a
--- /dev/null
+++ b/【实践课内】4.循环结构1/7-4 循环-4 的倍数.c	
@@ -0,0 +1,19 @@
+#include <stdio.h>
+
+int main() {
+    int n, count = 0;
+
+    scanf("%d", &n);
+
+    for (int i = 1; i <= n; i++) {
+        int x;
+
+        scanf("%d", &x);
+
+        if (x % 4 == 0) count++;
+    }
+
+    printf("%d\n", count);
+
+    return 0;
+}
diff --git a/【实践课内】4.循环结构1/7-4 循环-4 的倍数.jpg b/【实践课内】4.循环结构1/7-4 循环-4 的倍数.jpg
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