How to calculate sizeof() in c programming manually (without using computer)??

Here are some examples, I don't know how these answers (sizeof) were calculated??

(5 points) What's the output of this code snippet? (%zu prints a value of unsigned long integer, %p prints the address of a pointer) int (*p)[10]; p malloc(sizeofin) * 20); assume malloc() is successful printf"'sizeofp) %zum", sizeofp)); printf"sizeof*p)-%zuln", sizeof(*p)); printf("pl-%pm", (void *)p++); printf"p2 %pin", (void *)p); Output: sizeof(p) (1 point) sizeof(*p) - 40 (2 points)