Math I need help please help

Step-by-step explanation:
A= 13+8 = 21
B = 12+8= 20
C= 35-8= 27
D = 37-8= 29
Answer:
A. 21 B. 20 C. 27 D. 29
Step-by-step explanation:
To get the rule u would do 24-16=8 so for a and b u would +8 to the other number ans for c and d u would - 8 from the other number
Hope this helps :)