Adding and Subtracting Decimals Answers

Which number line correctly shows –3 – 1.5?

Aisha changed 1.45 + 2.38 to 1.5 + 2.4 in order to estimate the sum. What estimation method did she use?

Alexandra is scuba diving. A diving computer automatically records her depth every five minutes. The depth readings from her first 20 minutes of diving are shown in the table below.Elapsed time (in minutes)Depth (in meters)005–12.4510–9.715–22.9820–6.6Which best represents the greatest amount of change in her depth over a single 5-minute period?

While scuba diving, Rajeev dove to a depth of 12.6 feet below the surface of the water and then descended another 8.7 feet. What expression can be used to find Rajeev’s new position?

Lori had $126.89 in her bank account. She deposited $21.49 into it and then wrote a check for her car repairs for $156.61. What was the ending balance in her account?

The times for Erin’s five laps around the track were 56.6 seconds, 57.9 seconds, 57.5 seconds, 65.3 seconds, and 65.7 seconds. Using rounding to the nearest whole second as the only estimation technique, what is the total estimated time for Erin’s five laps in seconds?

What is the difference of –89.16 – 154.81?

Oni was timing her 100 meter sprints. Her first five sprints were 12.568 seconds, 11.426 seconds, 12.324 seconds, 11.981 seconds, and 12.601 seconds. Which two estimation techniques will give the same result for the total number of seconds for all five sprints?

Nadia is mountain climbing. She started at an altitude of 19.26 feet below sea level and then changed her altitude by climbing a total of 5,437.8 feet up from her initial position. What was Nadia’s altitude at the end of her climb?

Which expression is represented by the number line?