Question 1206309
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Some students may prefer horizontal number lines.
Other students may prefer vertical number lines.


If you like the 1st option, then start at -2.
Then move 7 units left to arrive at -9


If you prefer a vertical number line, then start at -2 and move down 7 units to arrive at -9.


Here are some real world applications of how to interpret -2 + (-7) = -9<ul><li>You are 2 meters under the ocean's surface. Going down another 7 meters will produce a final depth of 9 meters below the surface.</li><li>Your car is parked on the basement 2 level (B2) of a parking garage. Your friend parked his car 7 floors beneath yours, so his car is on level B9.</li><li>The temperature is -2 degrees C. After the temperature lowers by 7 degrees, it is now -9 degrees C.</li><li>You are 2 dollars in debt. This is represented by -2. Borrowing 7 more dollars brings the total debt to $9</li></ul>
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