Number Lines — Answer Key
Part A: Multiple Choice
Circle the best answer for each question.
1. A thermometer shows 20 degrees and drops 10 degrees. On a number line, where does the new temperature land?
A) 30 degrees
B) 10 degrees
C) 0 degrees
D) 15 degrees
A drop of 10 is a backward jump of 10, so 20 minus 10 lands on 10 degrees on the line.
2. Mia walks 40 steps, rests, then walks 30 more. Using a number line from 0, where does she end up?
A) 60 steps
B) 10 steps
C) 70 steps
D) 80 steps
Two forward jumps of 40 and 30 add to 70, so Mia ends at 70 on the step number line.
3. A game score starts at 50 points. The player loses 20, then gains 15. Where does the score land on a number line?
A) 35 points
B) 45 points
C) 65 points
D) 85 points
50 minus 20 is 30, and 30 plus 15 is 45, so the final score lands at 45 on the line.
4. A bus travels 100 miles, then 100 more, then turns back 50 miles. Using a 0 to 300 number line, where is the bus now?
A) 100 miles
B) 150 miles
C) 200 miles
D) 250 miles
100 plus 100 is 200, and 200 minus 50 is 150, so the bus sits at 150 on the mile line.
Part B: Fill in the Blank
Write the correct answer on each line.
1. A temperature rises from 10 degrees by 20 degrees. On a number line it reaches 30 degrees.
A rise of 20 is a forward jump of 20, so 10 plus 20 lands on 30 degrees on the line.
2. A frog jumps from 0 to 25, then back 10 on a number line. It lands on 15.
25 minus a backward jump of 10 equals 15, so the frog lands at 15 on the line.
3. A score of 60 loses 15 points. The new score on a number line is 45.
A loss of 15 is a backward jump of 15, so 60 minus 15 lands on 45 on the line.
4. A hiker is at mile 30 and walks 20 more miles forward. On a number line he reaches mile 50.
A forward jump of 20 from 30 lands on 50, so the hiker reaches mile 50 on the line.
5. A temperature of 25 degrees drops 5, then drops 5 more. The new reading is 15 degrees.
25 minus 5 is 20, and 20 minus 5 is 15, so the temperature lands on 15 degrees.