Number Lines - Glencoe
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glencoe.com Rational Numbers A Multi-Part Lesson 12-1 PART B C Number Lines BEACH Marcus and Silvio are at the beach. Marcus builds a sandhill 0.6 meter high. Silvio digs a ditch in the sand 0.8 meter deep. 0.8 m 0.6 m Just as you can graph integers on a number line, you can graph positive and negative fractions and decimals. Recall that positive numbers are to the right of zero on the number line and negative numbers are to the left of zero. Graph points on the number line to represent the hill and the ditch. Draw a number line from -1 to 1, with increments of 0.2. -0.4 -0.2 -0.6 -0.8 -1.0 0 0.2 0.4 0.6 0.8 1.0 The hill is above sea level. Its height is greater than zero on the number line. So, draw a dot at 0.6 to represent the hill. -0.4 -0.2 -0.6 -0.8 -1.0 0 0.2 0.4 0.6 0.8 1.0 The ditch is below sea level. Its depth is less than zero on the number line. So, draw a dot at -0.8 to represent the ditch. -0.4 -0.2 -0.6 -0.8 -1.0 0 0.2 0.4 0.6 0.8 1.0 Main Idea Model rational numbers. NGSSS MA.7.A.5.1 Express rational numbers as terminating or repeating decimals.
Transcript of Number Lines - Glencoe
the Results
1. Suppose Marcus built a hill 0.3 meter high. Would you graph the number to the left or right of zero? Explain.
2. Choose a decimal amount less than zero. Would it be graphed to the right or left of Silvio’s ditch? Explain.
3. Compare and contrast graphing positive and negative decimals on a number line.
You can also use models to graph rational numbers.
Graph - 3 _ 4 on a number line.
Model -
3 _ 4 using fraction tiles. Draw a number 1
414
14
14
-1 0 line from -1 to 0. Place the fraction tiles above the number line starting at zero.
Each fraction tile represents one fourth. Label 14
14
14
14
-1 0-
34
-
24
-
14
the number line with -
1 _ 4 , -
2 _ 4 , and -
3 _ 4 .
Remove the fraction tiles. Draw a dot at -
3 _ 4 .
-1 0-
34
-
24
-
14
and Apply
Graph each number on a number line. Use models if necessary.
4. -
4 _
5 5. -
1 _
4 6. -0.1 7. -4.5 8. 2
_ 3
9. 8.75 10. -
3 _
8 11. -5.75 12. 7
_ 10
13. -2.4
the Results
14. REASONING Jaclyn thinks that -
1 _
2 is greater than 1 _
4 because it is farther
from zero on the number line. Is her thinking correct? Explain.
15. Explain how you can use the number line to identify
fractions between -
3 _
4 and 3 _
4 . Then identify two fractions that are greater
than -
3 _
4 and less than 3 _
4 .
16. MAKE A CONJECTURE Write a rule that you can use to compare positive and negative values without a number line.
