Number lines can also be vertical, like a thermometer or a measure of elevation. 1. Discuss and write a sentence to describe the meaning of each statement. a. The weather forecaster predicts the temperature will be below zero. b. A submarine travels at 3000 feet below sea level. c. Badwater Basin in Death Valley, California, is 86 meters below sea level. 2. Mark each temperature on the thermometer shown. a. The highest temperature on record in the United States is 134ºF. It occurred in 1913 in Death Valley, California. b. The lowest temperature on record is 280ºF. It occurred at Prospect Creek Camp, Alaska. c. The lowest temperature recorded in the contiguous 48 states is 270ºF. It occurred in Montana. d. The highest winter average temperature in the United States is 78ºF, which occurs in Honolulu, Hawaii. 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 –30 –40 –50 –60 –70 –80 ºF Temperature Connection C01_SE_M04_T01_L01.indd 15 1/ 12/ 19 8:16 PM Answer Sample answers. 1a. The temperatures will be negative. 1b. The submarine travels 3000 feet below the sea or at a height of 23000 feet. 1c. Badwater Basin is at an elevation of 286 meters. 2. 140 134°F a. 78°F d. –70°F c. –80°F b. 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 –30 –40 –50 –60 –70 –80 ºF C01_TIG_M04_T01_L01_007-022.indd 1501_TIG_M04_T01_L01_007-022.indd 15 14 /01 /19 4:09 PM14/ 01/ 19 4:09 PM M4-16 • TOPIC 1: Signed Numbers M4-16 • TOPIC 1: Signed Numbers 3. Which is colder, the lowest temperature recorded in Alaska or the lowest temperature recorded in Montana? How do you know? 140 130 120 110 100 90 80 70 60 50 40 30 20 10 0 –10 –20 –30 –40 –50 –60 –70 –80 ºF 4. Yadi and Eric were comparing 25 degrees to 227 degrees. • Yadi wrote 25 , 227 and justifi ed her comparison by stating that the further a number is from zero, the greater the number. • Eric wrote 25 . 227 and justifi ed his comparison by stating that the greater temperature will be above the second temperature on a thermometer. Who is correct? Explain your choice. 5. Plot each set of temperatures on the thermometer. Then insert a . or , symbol to make each number sentence true. a. 226°F 231°F b. 26°F 217° F c. 29°F 8°F 6. Order the temperatures from least to greatest. 25°F 233°F 0°F 105°F 240°F 25°F 67°F C01_SE_M04_T01_L01.indd 16 1/ 12/ 19 8:16 PM Answers 3. The lowest temperature in Alaska is colder than the lowest temperature in Montana because 280 is below 270 on the vertical number line. 4. Eric is correct. On a vertical number line, numbers further up the number line have a greater value, regardless of the distance from 0 of the two numbers. 5. 5a. 2268F . 2318F 5b. 268F . 2178F 5c. 298F , 8 8F 6. 2408F, 2338F, 258F, 08F, 258F, 678F, 10 58F 50 –26°F –6°F 8°F –9°F –17°F –31°F 40 30 20 10 0 –10 –20 –30 –40 –50 ºF C01_TIG_M04_T01_L01_007-022.indd 1601_TIG_M04_T01_L01_007-022.indd 16 14 /01 /19 4:09 PM14/ 01/ 19 4:09 PM LESSON 1: Human Number Line • M4-19 Answers 1. 0 is the benchmark on a number line. All values to the right are positive and all values to the left are negative. 2. On a number line, op- posites are on opposite sides of 0 and the same distance from 0. Sample answers. 3a. A positive rational number is greater because it is farther to the right. 3b. A positive rational number is greater because it is always to the right of 0. 3c. Zero is greater because it is always to the right of the negative numbers. 3d. The number that is farther to the right is always greater. 3e. The number that is farther to the right is always greater. NOTES LESSON 1: Human Number Line • M4-19 TA L K th e TA L K Putting It All Together 1. What does 0 mean on a number line? 2. What does opposite mean in terms of a number line? 3. Compare the types of numbers. Use what you know about number lines to explain your reasoning. a. Which is greater—a negative or a positive rational number? b. Which is greater—zero or any positive rational number? c. Which is greater—zero or any negative rational number? d. How do you decide which of two numbers is greater if both numbers are positive? e. How do you decide which of two numbers is greater if both numbers are negative?