Bell Work: Solve 2 x 4 – 3 x 2 – x 2

Answer: = 5

Lesson 12: Symbols of Inclusion, Order of Operations

Symbols of Inclusion: In lesson 11 we found that the simplification of x 2 Is 10 because we have agreed to do the multiplication first and do the addition.

Parentheses, brackets, braces and bars are all called symbols of inclusion and can be used to help us emphasize the meaning of our notation.

Using these symbols x 2 Can be written in multiple ways x (3 x 2)4 + 3 x x 2

Each of the notations emphasizes that 3 is to be multiplies by 2 and that 4 is to added to this product. A further benefit of the use of symbols of inclusion is that a nonstandard order of operations can be indicated.

For example, we can use parentheses to indicate that 4 is to be added to 3 and the result multiplied by 2. 2(3 + 4) (3 + 4)2

Order of Operations: To simplify numerical expressions that contain symbols of inclusion, we begin by simplifying within the symbols of inclusion. Then we simplify the resulting expression, remembering that multiplication is performed before addition.

Example: Simplify 4(3 + 2) – 5(6 – 3)

Answer: 4(3 + 2) – 5(6 – 3) = 4(5) – 5(3) = 20 – 15 = 5

Example: Simplify -3(2 – 3 + 5) – 6(4 + 2) – 3

Answer: -3(2 – 3 + 5) – 6(4 + 2) – 3 = -3(4) – 6(6) -3 = -12 – 36 – 3 = -51

Example: Simplify -2(-3 – 3)(-2 – 4) – (-3 – 2) + 3(4 – 2)

Answer: -2(-3 – 3)(-2 – 4) – (-3 – 2) + 3(4 – 2) = -2(-6)(-6) – (-5) + 3(2) = = -61

When the expression is written in the form of a fraction, we begin by simplifying both the numerator and the denominator. Then we have our choice of dividing or leaving the result in the form of a fraction.

Example: Simplify 5(-5 + 3) + 7(-5 + 9) + 2 (4 – 2)

Answer: 5(-5 + 3) + 7(-5 + 9) + 2 (4 – 2) = 5(-2) + 7(4) = = = 2

Example: Simplify -3(4 – 2) – (-5) 4 – (3)(-3)

Answer: -3(4 – 2) – (-5) 4 – (3)(-3) = -3(2) – (3)(-3) = = -1 13

HW: Lesson 12 #1-30 Due Tomorrow