Addition and subtraction integers

1. ADDITION AND SUBTRACTION OF INTEGERS The University of Texas at Dallas

2. Introduce symbols + (plus) - (minus)

3. ADDING INTEGERS We can model integer addition with tiles. Represent -2 with the fewest number of tiles Represent +5 with the fewest number of tiles. The University of Texas at Dallas

4. ADDING INTEGERS What number is represented by combining the 2 groups of tiles? Write the number sentence that is illustrated. -2 + + 5 = + 3 The University of Texas at Dallas + 3

5. ADDING INTEGERS Use your red and yellow tiles to find each sum. -2 + -3 = ? The University of Texas at Dallas ANSWER + = -5 -2 + -3 = - 5

6. ADDING INTEGERS The University of Texas at Dallas - 6 + + 2 = ? + = - 4 + = + 1 - 3 + + 4 = ? ANSWER ANSWER - 6 + + 2 = - 4 - 3 + + 4 = + 1

7. Addition Rule 1) When the signs are the same, ADD and keep the sign. (-2) + (-4) = -6 2) When the signs are different, SUBTRACT and use the sign of the bigger number. (-2) + 4 = 2 2 + (-4) = -2

8. -1 + 3 = ? -4 -2 2 4 Answer Now Negative one plus three is equal to two.

9. -6 + (-3) = ? -9 -3 3 9 Answer Now Negative six plus negative three is equal to negative nine.

10. Karaoke Time! Addition Rule: Sung to the tune of “Row, row, row, your boat” Same sign, keep and add ! Different sign: subtract, Take the sign of the bigger number, Then you will be exact ! Let’s Go

11. When subtracting, change the subtraction to adding the opposite ( keep - change - change ) and then follow your addition rule. Example #1 : - 4 - (-7) - 4 + ( + 7) Diff. Signs --> Subtract and use larger sign. 3 Example #2 : - 3 - 7 - 3 + ( - 7) Same Signs --> Add and keep the sign. -10

12. Which is equivalent to -12 – (-3)? Answer Now 15 -9 -15 9 Negative twelve minus negative three is equal to negative nine.

13. 7 – (-2) = ? Answer Now -9 -5 5 9 Seven minus negative two is equal to nine.