Lsb*Msb in a 4 digit int

//this program is used to mult the first and 4th digit of 4 digit int
// 7023 is used for testing
#include <stdio.h>
int num, num1, num2, num3, num4;
int main(void) {
    printf("Enter a int that consists of 4 digits\n");
    scanf_s("%d", &num);
    num1 = num % 10; // Lsb
    printf("%d", num1);
    num3 = num / 1000; //msb
    printf("%d", num);
    num4 = num1 * num3;
    printf("the sum of * of the Lsb and Msb = \n");
    printf("%d", num4);
}