Finding the change in temperature question

[maxpain2017]

Hello all,

Currently stuck on this question:

A temperature is at -9 degree celsius. Over 2 hours the temperature had increased to +5 degrees. What is the total degree in change over 2 hours?

The way I figured to answer this question is by just writing out the list of numbers and counting:

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5


I got 14 degrees change?

I'm not sure if this is correct however. Are you supposed to count "0" as well? if not, then I'm assuming the answer is 13?

Any feedback is great appreciated!

 

[stapel]

A temperature is at -9 degree celsius. Over 2 hours the temperature had increased to +5 degrees. What is the total degree in change over 2 hours?

The way I figured to answer this question is by just writing out the list of numbers and counting:

-9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5

I got 14 degrees change?

This is the correct answer.

Are you supposed to count "0" as well?

Is it a number that the temperature had to pass on its way to +5? Then ya count it!

(By the way, this is why it's easy to get the number of years wrong, when you're measuring from BC to AD. There is no "Year Zero". The dates go from 1BC ["one year before"] to 1AD ["first year of"].)

 

[JeffM]

Suppose the temperature had gone from 5 to 19. You would simply subtract plus 5 from plus 19, getting a change of 14. This is EXACTLY why we say that subtracting a negative number has the same effect as adding the equivalent positive number.

\(\displaystyle 9 - (-\ 5) = 9 + 5 = 14.\)

 

[maxpain2017]

It is definitely more clear for me now.

Thank you all again for multiple explanations.