1. Warm-up Please put your homework in the orange basket
Preston was collecting coins. He got 7 coins from his piggy bank and 2 coins from his brother. His father gave Preston 12 coins. Preston gave 14 of the coins to his friend Cara. How many coins did Preston have left?

2. Monday, September 19, 2016 Warm-up
Please copy your homework into your assignment book.
Adding and Subtracting Decimals
Practice
Homework: Adding and Subtracting Decimals Worksheet
Quiz: Wednesday
Test: Rational Numbers (Fractions and Decimals) Monday

3. Adding and Subtracting Decimals

4. Essential Question: How do I add and subtract decimals?
Always line up decimals
Add and subtract like you always do
Bring decimal straight down in your answers

5. You can add a zero to help keep everything lined up
Adding
Examples:
Put the first number on the top of the second number and line up the decimals.
You can add a zero to help keep everything lined up
When adding or subtracting you always start from the right and work left.
15.85

6. Add a zero to line up everything
When there is
not a decimal
put one
behind the
number.
Line up the decimal
Add a zero to line up everything
22.44

7. Add a zero to line up everything
-8.33
Line up
the decimal
Add a zero to line up everything +
Same signs
Add – keep the sign

8. Subtracting Examples: 5.34 -2.08 5.34 -2.08 3.26
Put the first number on the top of the second number and line up the decimals.
Different signs
Take difference
3.26

9. -38.59 – (-7.81) -38.59 + 7.81 -30.78 + Line up the decimal
Line up
the decimal +
-30.78
Subtract to add when negatives are used.
Different signs take difference

10. Add zeros to line up everything, then subtract
28 –
When there is
not a decimal
put one
behind the
number.
Add zeros to line up everything, then subtract 7 9 9
000 . 1 2 8 9

11. Independent Practice
When instructed to do so, grab a purple pre-algebra book
Complete: pg. 176 #’s 14-25
You will turn this in before you leave class today.