1. Do Now 11/14/11 Copy HW in your planner. Copy HW in your planner. Text p. 102, #10-40 evens, #42, 43, 48, & 49 Text p. 102, #10-40 evens, #42, 43, 48, & 49 In your journal, define the word “decimal.” Then describe as many situations in real-life as you can where you might need to add or subtract decimals. In your journal, define the word “decimal.” Then describe as many situations in real-life as you can where you might need to add or subtract decimals.

2. Section 3-1 Adding & Subtracting Decimals Add & subtract decimal numbers by lining up the decimal point. by lining up the decimal point. 1.2 +0.87 2.07 H U N D R E D T H s T E N T H S O n e s 1.2 + 0.87 0 Use a zero as a placeholder so that both numbers are in the same place value

3. 9 +3.245 12.245 H U N D R E D T H s T E N T H S O n e s 9 + 3.245. Use zeros as a placeholders so that both numbers are in the same place value. 000 T H O U S A N D T H s Put the decimal point after any whole numbers.

4. 12.49 – 7.2 5.29 H U N D R E D T H s T E N T H S O n e s 12.49 – 7.2 0 Use a zero as a placeholder so that both numbers are in the same place value T e n s

5. 14 – 7.32 6.68 H U N D R E D T H s T E N T H S O n e s 14 – 7.32. Use zeros as a placeholders so that both numbers are in the same place value. 00 T e n s Put the decimal point after any whole numbers.

6. |35| = 35 35 + 18 Adding Two Integers with SAME signs To add two integers with the SAME signs, find the sum of their absolute values. Use the sign of the two integers. To add two integers with the SAME signs, find the sum of their absolute values. Use the sign of the two integers. |18| = 18 35 + 18 = 53 = 53 |-35| = 35 -35 + (-18) |-18| = 18 35 + 18 = 53 - Remember this? “Adding Integers”

7. |-35| = 35 -35 + 18 Adding Two Integers with DIFFERENT signs To add two integers with DIFFERENT signs, find the difference of their absolute values. Use the sign of the integer with the greater absolute value. To add two integers with DIFFERENT signs, find the difference of their absolute values. Use the sign of the integer with the greater absolute value. |18| = 18 35 – 18 = 17 - Because 35 has a greater absolute value than 18 the answer is “negative”. Remember this? “Adding Integers”

8. Negative or Positive? Without solving the problem, decide whether the sum will be positive, negative, or zero. Without solving the problem, decide whether the sum will be positive, negative, or zero. 7.2 + (-4.36) positive -13.3 + 11.76 negative -3.3 + 3.3 zero -7.3 + (-6.72) negative

9. “Subtracting Integers” When subtracting two integers, ADD the OPPOSITE of the second number to the first. -8 – 15 = Instead of subtracting ADD the OPPOSITE!! -8 + (-15) = ADD the OPPOSITE -23 Do the “OPP-OPP” “Opposite-Opposite” Remember this?

10. Negative or Positive? Without solving the problem, decide whether the sum will be positive, negative, or zero. (HINT: write the problem as a sum). Without solving the problem, decide whether the sum will be positive, negative, or zero. (HINT: write the problem as a sum). 1.7 – (-2.2) positive -1.36 – 1.1 negative -0.14 – (-0.14) zero 7.3 – 8 negative 1.7 + (+2.2) -1.36 + (-1.1) -0.14 + (+0.14) 7.3 + (-8) Add the Opposite !!!

11. 62.82 – 32.7 30.12 HUNDREDTHs TENTHS Ones 32.7 + (-62.82) Use a zero as a placeholder so that both numbers are in the same place value. Tens |32.7| = 32.7 |-62.82| = 62.82 62.82 – 32.7 - Because 62.82 has a greater absolute value than 32.7 the answer is “negative”. 0

12. 5.23 + 9.1 14.33 HUNDREDTHs TENTHS Ones -5.23 – 9.1 Use a zero as a placeholder so that both numbers are in the same place value. - 0 -5.23 + (-9.1) Add the Opposite !!! To add two integers with the SAME signs, find the sum of their absolute values. Use the sign of the two integers

13. “Real-Life” During one month in the United States, 492.23 million commuter trips were taken on buses, and 26.331 million commuter trips were taken on light rail. How many more trips were taken on buses than on light rail? 492.230 – 26.331 – 26.331 465.899 465.899 million more trips were taken on buses than on light rail

14. 24 Homework Text p. 102, #10-40 evens, #42, 43, 48, & 49