Answer:
3
Step-by-step explanation:
Because when you do 7 - 3 it gives you 4. You check this by adding 4 to 3 and you will get 7. Also you can figure it out the number by subtracting 7 and 4 to get your answer.
Your answer will be 3.
I hope this helped. I am sorry if you get this wrong. Have a wonderful day.