Numbers and Operations

Open Ended

In just a word, what do you think of when you think of math?

List up to 5 words

​Numbers

​Operations

• Positive Numbers

• Negative Numbers

• Zero

• Unknown/Variables
  letters are used to represent unknowns and variables

• Addition

• Subtraction

• Multiplication

• Division

• Exponents

​You will have to be careful, the negative sign and subtraction symbol are the same, if not similar.

​Identifying when " - " is a negative sign and when it is a subtraction symbol.

​Examples of Negative:
-3
-4x
4 + (-5)
4 + -5

​Examples of Subtraction:
5 - 2
2x - 5
4 - 5x
2x³ - 4x²

​Do you notice any patterns?

Open Ended

What pattern(s) did you notice between or within each group, Negative sign and Subtraction symbol

​If there is a number, variable(letter), or parenthesis in front of the " - ", then it is subtraction.

If there is nothing or another operation directly in front of the " - ", then it is a negative sign.

​Note: when there are two signs right next to each other, they reduce to one sign.
++ = + Addition of a positive is just addition.
- - = + Subtraction of a negative is also just addition.

+ - = - Addition of a negative is really subtraction.
- + = - Subtraction of a positive is just subtraction.

​These rules apply to multiplying as well

​

Multiple Choice

Identify each "-" as either a negative symbol or a subtraction symbol.

-2x + 4

​ ​ ​

• Subtraction

• Negative

Multiple Choice

Identify the "-" as either a negative symbol or a subtraction symbol.

2x - 4

​ ​ ​

• Subtraction

• Negative

Multiple Choice

Identify the "-" as either a negative symbol or a subtraction symbol.

-2x - -4

​ ​ ​

• The first and third "-" are negatives, the middle(2nd) "-" is subtraction.

• The first and third "-" are subtraction, the middle(2nd) "-" is negative.

• They are all subtraction symbols!

• They are all negative signs!

​Using the Calculator.

​Lets plug these into the calculator
(be cautious: which button do you use?)

1. 10 + 4

2. 10 - 4

3. 10 + -4

4. 10 - -4

5. 4 + 10

6. -4 + 10

​Order of Operations

​P E M D A S

​Order of Operations
for evaluating and simplifying

PEMDAS​
P arenthesis
E xponents
M ultiplication
D ivision
A ddition
S ubtraction

​However we are only going to focus on the last two groups today:

Multiply/divide before add/subtract when evaluating.

​Examples:
1. 2(3) + 4

​ 2. 4 + 2(3)

​3. 12/2 - 1

​Assignment: Quizizz