1-4Adding & Subtracting Integers :1-4Adding & Subtracting Integers Adding Integers With: Same Signs (+) + (+) (-) + (-) Rule: Add the ABSOLUTE VALUE of each addend, and give the sum the sign of both addends. In other words: (+) + (+) = + (-) + (-) = - Different Signs (-) + (+) (+) + (-) Rule: Subtract the ABSOLUTE VALUE of each addend (HIGH - LOW) and give the sum the sign of the LARGEST absolute value.


Slide 2:Subtracting Integers: Rules: Change the SUBTRACTION SIGN to an ADDITION sign. Change the sign of the SECOND addend to its OPPOSITE sign. This is now an addition problem! Follow the rules for adding integers! There are THREE questions that will help you evaluate ANY integer expression! 1. Do I change any signs? 2. Do I add or subtract the absolute values? 3. What is the sign of my sum? 1-4Adding & Subtracting Integers


Slide 3:1-4Adding & Subtracting Integers Ex. 1. Evaluate all sums and differences. -8 + -5 Will signs be changed? NO! (Because it is an addition problem! Only change on subtraction) Will absolute values be added or subtracted? ADD! (Because addends are the same signs!) Will my solution be + or - ? NEGATIVE! (Because both addends are negative!) THINK: -8 + -5 = 8 + 5 Then give it its negative sign! Therefore: -8 + -5 = -13


Slide 4:1-4Adding & Subtracting Integers Ex. 2. Evaluate all sums and differences. -7 + 2 Will signs be changed? NO! (Because it is an addition problem! Only change on subtraction) Will absolute values be added or subtracted? SUBTRACT! (Because addends are different signs!) Will my solution be + or - ? NEGATIVE! (Because -7 is the largest absolute value!) THINK: -7 + 2 = 7 - 2 Then give it its negative sign! Therefore: -7 + 2 = -5


Slide 5:1-4Adding & Subtracting Integers Ex. 3. Evaluate all sums and differences. 11 + -4 Will signs be changed? NO! (Because it is an addition problem! Only change on subtraction) Will absolute values be added or subtracted? SUBTRACT! (Because addends are different signs!) Will my solution be + or - ? POSITIVE! (Because 11 is the largest absolute value!) THINK: 11 + -4 = 11 - 4 Then give it its positive sign! Therefore: 11 + -4 = 7


Slide 6:1-4Adding & Subtracting Integers Ex. 4. Evaluate all sums and differences. -9 + 21 Will signs be changed? NO! (Because it is an addition problem! Only change on subtraction) Will absolute values be added or subtracted? SUBTRACT! (Because addends are different signs!) Will my solution be + or - ? POSITIVE! (Because 21 is the largest absolute value!) THINK: -9 + 21 = 21 - 9 Then give it its positive sign! Therefore: -9 + 21 = 12


Slide 7:1-4Adding & Subtracting Integers Ex. 5. Evaluate all sums and differences. -11 - 12 Will signs be changed? YES! (Because it is a subtraction problem!) -11 + -12 Will absolute values be added or subtracted? ADD! (Because addends are same signs!) Will my solution be + or - ? NEGATIVE! (Because both addends are negative!) THINK: -11 + -12 = 11 + 12 Then give it its negative sign! Therefore: -11 - 12 = -11 + -12 = -23


Slide 8:1-4Adding & Subtracting Integers Ex. 6. Evaluate all sums and differences. -14 – (-7) Will signs be changed? YES! (Because it is a subtraction problem!) -14 + (+7) Will absolute values be added or subtracted? SUBTRACT! (Because addends are different signs!) Will my solution be + or - ? NEGATIVE! (Because -14 is the largest absolute value!) THINK: -14 + (+7) = 14 - 7 Then give it its negative sign! Therefore: -14 – (-7) = -14 + (+7) = -7


Slide 9:1-4Adding & Subtracting Integers Ex. 7. Evaluate all sums and differences. 18 – 35 Will signs be changed? YES! (Because it is a subtraction problem!) 18 + (-35) Will absolute values be added or subtracted? SUBTRACT! (Because addends are different signs!) Will my solution be + or - ? NEGATIVE! (Because -35 is the largest absolute value!) THINK: 18 + (-35) = 35 - 18 Then give it its negative sign! Therefore: 18 – 35 = 18 + (-35) = -17