Model with a number line
-5 + 9
4
Change to addition and then model with counters
-4 - 6
-10
Change to addition
-2 - 3
-5
Kayla began a science experiment with 18 grams of an unknown solid. During the experiment, the change in the mass of the solid was – 7 grams. What was the mass of the solid at the end of the experiment?
18 + (-7) = 25 grams
Model with a number line
-12 + 5
-7
Change to addition and then model with counters
4 - 11
-7
-10 + 30
20
Clara and her family are vacationing in the Netherlands. They began a tour of the North Sea coastline at an elevation of –8 feet. By the end of the tour, their elevation had decreased by 5 feet. What was their elevation at the end of the tour?
-8 - 5
-8 + (-5) = -13 ft
Change to addition and then model with counters
15 - (-7)
22
Change to addition
21 - (+5)
16
The temperature on February 2 in Lake City was 14°F. The temperature in Ellenville the same day was –6°F. How much warmer was it in Lake City than in Ellenville?
14 - (-6)
14 + 6 = 20°F
Change to addition
-27 - (-3)
-24
Bryant was playing the video game Ship, Ship Ahoy! He began Level 2 with 15 points but soon got –6 points because his character fell overboard. What is Bryant's total score now?
15 + (–6) =9 points
Change to addition
-10 - 11 - (-3)
-18
-10 + (-2) + (- 5)
-17
The afternoon temperature in Biscoff Bay was –2°F. By midnight, a warm front moved in and the temperature rose to 11°F. What was the change in temperature from afternoon to midnight?
11 – (–2)
11 + 2 = 13°F