7th Grade Math- adding integers with different signs

Mathematics
Tutor: None Selected Time limit: 1 Day

Need HELP!! The temperature outside dropped 13 degrees Fahrenheit in 7 hours.  The final temperature was -2 degrees Fahrenheit.  What was the starting temperature?

Sep 10th, 2015

Thank you for the opportunity to help you with your question! Hope your day is going well!

You can set up an equation for this, and figure it out very methodically.

We know that the temperature lost 13 degrees, but we do not know what the original temperature was. So, all you have to do, is call x the original temperature

x-13=-2

It is equal to -2 because that is the final temperature.

Last thing we need to do, is solve for x

x-13=-2 (add thirteen to both sides)

x=11

Therefore, the original temperature was 11 degrees farenheit.

Please let me know if you need any clarification. I'm always happy to answer your questions. Leave a positive review if you are happy!
Sep 10th, 2015

My son still doesn't understand this answer.  Is there a more simplified way to explain to him?

Sep 10th, 2015

Okay,

We know that the end result is that the final temperature is -2.

But we know that the original temperature was 13 degrees higher.


If we combine these two numbers, we will get the original temperature. Combine as if we add them them. But since the two is negative, it is as though we are subtracting them.

13-2=11.


Does this help?

Sep 10th, 2015

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Sep 10th, 2015
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Sep 10th, 2015
Dec 8th, 2016
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