pre-alg 3.1 multiplying integers & decimals

Pre-Algebra

3.1 & 3.2

Multiplying Integers & Decimals

Part 1 & 2

Think-Pair-Share

+ + = +

- - = +

- + = -

+ - = -

Rules:

HChow did it come about that

9 + 9 + 99, 3 times

9 x 3

Ancient

Babylonians

~4000 yrs ago

Multiplication = repeated addition

What is 9, 3 times?9 x 3

Division = repeated subtraction

9 + 9 + 9

12 - 3 - 3 - 3 - 3

12 ÷ 3How many 3's are in 12?

+ + = +

- - = +

- + = -

+ - = -

Rules: - = opposite, + =

x

Face in the direction of the sign

+- Walk in the

direction of the sign

| | | | | | | | | | | 0 1 2 3 4 5-1-2-3-4-5

+- + -

+-

x

Face in the direction of the sign

+-

Walk in the direction of the sign

| | | | | | | | | | | 0 1 2 3 4 5-1-2-3-4-5

+- + -

+- 10 5

xFace in the

direction of the sign

+-

Walk in the direction of the sign

| | | | | | | | | | | 0 1 2 3 4 5-1-2-3-4-5

+- + -

+- 5.1 -7

xFace in the

direction of the sign

+-

Walk in the direction of the sign

| | | | | | | | | | | 0 1 2 3 4 5-1-2-3-4-5

+- + -

+- -2.7 -2.3

xFace in the

direction of the sign

+-

Walk in the direction of the sign

| | | | | | | | | | | 0 1 2 3 4 5-1-2-3-4-5

+- + -

+- -3.8 13

Determine the sign of the product. SMOTD

x x x

Rules: Positive product = mult. even amount of negatives

Negative product = mult. odd amount of negatives.

Order of Operations: SMOTD

How to drive a car.

Unlock the car.

Sit on the seat.

Enter key into ignition, turn.

Put on your seatbelt.

Press brake, shift to "drive."

Check mirrors.

P

E

MD

AS

Order of Operations:

PEMDAS

PEMDASPEDMASPEMDSAPEDMSA

HCP

E

MD

AS

P

E

MD

AS

P

E

MD

AS