Review of last week:

Review of last week:

Review of last week:

= + - -5 - 8

-9 - 10

= + - -6 - - 10

-3 - - 15

Review of last week:

Pre-Algebra

Unit 2 Lesson 8 & 9

Adding Decimals

Part 1 & 2

What do you know about adding decimals?

Think-Pair-Share

What is a decimal?A point or dot used to separate the whole number part from the fractional part of a number.

Rules:

Same sign (+ +, - -)

add numbers together, keep sign

Different signs (+ - , - +)

find difference, take sign of higher number

Examples:

1) 2.8 + 14.5

2) -3.3 + 14.2

3) -9.17 + (-4.27)

4) 10.8 + -4.5

Same/Diff. Problem

Activity:

SMOTDYour decimal: Your Birthday! month.day

Example: August 11 = 8.11

Example: January 6 = 1.06

+ +

- -

+ -

- +

Activity:

1)

1)

1)

1)

Comparing expressions

Comparing expressions

Inverse operations and decimals

y + 33.2 = 12.5

y - - 23.7 = 48.1

Inverse operations and decimals

x + 14.5 = 39.4 x - 19.2 = 8.3

x - (- 6.6) = 7.7 x - (-10.3) = - 4.5