Add and Subtract Integers Lesson 1 (from 3/2)

Add and Subtract Integers Rules

Integer

positive or negative whole numbers

...-3, -2, -1, 0, 1, 2, 3, ...

Sign of a Number

positive or negative symbol used with the number

 $+6=6$  is positive 6

 $-6$   is negative 6

 $6\$  and  $-6$  have different signs

 $6$  is positive and  $-6$   is negative

 $13\ +\ \left(-8\right)$  
is the same as
 $13-8$  

signs are different

 $13\$  is positive and  $-8$  is negative

Rule: subtract the numbers, keep the sign of the larger number

 $13-8=5$ ; $5$  is positive because 13 is larger than $8$  

 $-12\ +\left(-6\right)$  
is the same as
 $-12-6$  

Signs are the same

 $-12$  and  $-6$  are both negative

Rule: add the numbers and keep the sign
 $-12-6=-18$ ;

 $-12$  and $-6$  are negative, add them and keep the answer negative

Multiple Choice

Are the signs the same or different?

 $-16\ +\ 8$  

• same signs--add and keep the sign

• different signs--subtract and keeps the sign of the larger number

Multiple Choice

 $-18\ -12$  

• same signs

• different signs

Multiple Choice

 $16+\left(-20\right)$  

• same signs

• different signs

Multiple Choice

 $12+10$  

• same signs

• different signs

Multiple Choice

 $-15\ +\left(-8\right)$  

• same signs

• different signs

Multiple Choice

 $-12\ -7$  

• same signs

• different signs

Multiple Choice

 $12\ -15$  

• same signs

• different signs

 $15-\left(-8\right)$ 
is the same as
 $15+8$  

 $-10-\left(-2\right)$  
is the same as
 $-10+2$  

 $-10-\left(-2\right)$                                           $15-\left(-8\right)$  
is the same as                                       is the same as
 $-10+2$                                                  $15+8$  

The first number stays the same.

The second number changes to a positive

Multiple Choice

 $16\ -\ \left(-3\right)$  

is the same as

•  $16+3$  

•  $-16+3$  

Multiple Choice

 $-12\ -\ \left(-5\right)$  

is the same as

•  $-12+5$  

•  $12+5$  

Multiple Choice

 $8\ -\ \left(-6\right)$  

is the same as

•  $-8+6$  

•  $8+6$  

Multiple Choice

 $-13-\left(-4\right)$  

is the same as

•  $-13+4$ 

•  $13+4$  

•  $-13-4$  

•  $13-4$  

Multiple Choice

 $15+6$  

is the same as

•  $-15-\left(-6\right)$  

•  $15-\left(-6\right)$  

Multiple Choice

 $-11+18$  

is the same as

•  $-11-\left(-18\right)$  

•  $11-\left(-18\right)$  

Practice all of the Rules

Multiple Choice

 $8+\left(-3\right)$  

•  $5$  

•  $-5$  
  

•  $11$ 

•  $-11$  

Multiple Choice

 $-7+\left(-6\right)$  

•  $1$  

•  $-1$  

•  $13$  

•  $-13$  

Multiple Choice

 $15-8$  

•  $7$  

•  $-7$  

•  $23$  

•  $-23$  

Multiple Choice

 $-12-6$  

•  $6$  

•  $-6$  

•  $18$  

•  $-18$  

Multiple Choice

 $-8+17$  

•  $9$  

•  $-9$  

•  $25$  

•  $-25$  

Multiple Choice

 $-18-\left(-4\right)$  

•  $14$  

•  $-14$  

•  $22$  

•  $-22$  

Multiple Choice

 $16-\left(-3\right)$  

•  $13$  

•  $-13$  

•  $19$  

•  $-19$  

Multiple Choice

 $10-19$  

•  $9$  

•  $-9$  

•  $29$  

•  $-29$  

Poll

How are you feeling about adding and subtracting integers?