In this Grade 7 lesson from Big Ideas Math, Course 2, students learn how to add integers with the same sign, different signs, and opposite signs using integer counters and number lines. The lesson covers key rules for determining whether a sum is positive, negative, or zero, including the Additive Inverse Property, which states that an integer and its opposite always sum to zero. Students practice applying absolute values to find sums and develop general rules for all cases of integer addition.
Section 1
Adding Integers Using Number Lines
To add integers using a number line: Start at the first integer, then move right for positive addends or left for negative addends. The distance moved equals the absolute value of the second integer: means start at and move units in the direction determined by the sign of .
Section 2
Adding Two Numbers with the Same Sign
Expand to review the lesson summary and core properties.
Section 1
Adding Integers Using Number Lines
To add integers using a number line: Start at the first integer, then move right for positive addends or left for negative addends. The distance moved equals the absolute value of the second integer: means start at and move units in the direction determined by the sign of .
Section 2
Adding Two Numbers with the Same Sign