Respuesta :

StarDev

Answer: You are missing a 4.

Step-by-step explanation: If you said the answer is 20, 4 is missing. We can add up the follow equation before putting 4.

(4 + 3) + (4 + 5)

   7     +    9 = 16 + 4 = 20.

Hence, 20 is your answer.
I’m pretty sure the mistake is here you are missing 4