Answer:
The missing number is 2
Step-by-step explanation:
43 - 13 = 30
13 - 10 = 3
10 - 8 = ?
10 - 8 = 2
30 - 3 = 27
3 - ? = 1
3 - 1 = 2
3 - 2 = 1
? = 2