Answer:
Step-by-step explanation:
To make this statement true, we want to make it so that when -20 is "<em>something</em>'d" to 18, we get -2.
Let's try all the common operators first - add, subtract, multiply, divide.
Let's try add.
If we put a plus sign there:
Adding a negative is the same as subtracting a positive.
This is true! 18 - 20 is indeed -2. This means + is the right operator.
For fun, let me briefly go over what happens with all the other operators.
Subtract:
Multiply:
Divide:
Hope this helped!