Predict the result
Predict the sign of four plus negative seven.
The two addends have opposite signs.

Set up the model
Compare their absolute values, four and seven.
The absolute value of negative seven is seven. The negative addend has greater absolute value.

Work the example
Subtract four from seven to get three.
Keep the sign of negative seven, the addend with greater absolute value.
Four plus negative seven equals negative three.

Check the result
Now add negative eighteen and eleven.
Compare the absolute values, subtract, and choose the sign. Take eight seconds to think.
[Eight-second silent pause to work; the answer remains hidden.]
Eighteen minus eleven equals seven. The negative addend has greater absolute value.
Negative eighteen plus eleven equals negative seven.

Interpret the result
For opposite signs, compare the absolute values.
If they differ, subtract and keep the sign of the addend with greater absolute value.
If the absolute values are equal, the sum is zero.