Add and subtracting using both positive and negative number

[mrb7695]

simplify numerical expression
-21+(-17)-11+15-(-11)
I get the correct answer with a calculator of -24 this matched the answer in the text. However, when i try to work it out long hand i get -22. Where am I going wrong?

 

[galactus]

Re: Add and subtracting using both positive and negative num

Neither is correct. The solution is in between those values. I get -23. Do you have the problem written EXACTLY as it is in the book?.

Without your work, I do not know where you went wrong. But, since you are only off by 1, recheck your adding and subtracting.

 

[mrb7695]

Re: Add and subtracting using both positive and negative num

NO sorry there was a wrong number in the oringinal post should have read
simplify numerical expression
-21+(-17)-11+15-(-10)=-24
i keep getting -22
using my calculator i get -24 the text says the answer is -24 but when i work it out i get -22

 

[mrb7695]

Re: Add and subtracting using both positive and negative num

-21+(-17)-11+15-(-10)
-38+(-11)+15+(-10)
-27+15+(-10)
-12+(-10)
-22

this is what I got but text says the answer should be -24

 

[tkhunny]

Re: Add and subtracting using both positive and negative num

-21+(-17)-11+15-(-10)
-38+(-11)+15+(-10)
-27+15+(-10)
-12+(-10)
-22

this is what I got but text says the answer should be -24

-21+(-17)-11+15-(-10)
-21 - 17 - 11 + 15 + 10
-38 - 11 + 15 + 10
-49 + 15 + 10
-34 + 10
-24
Yup.

 

[JeffM]

Re: Add and subtracting using both positive and negative num

-21+(-17)-11+15-(-10)
-38+(-11)+15+(-10) NO -38 + (-11) + 15 - (-10) You have + (-10)
-27+15+(-10) NO -49 + 15 - (-10). -38 + (-11) = -49. If it is 38 degrees below zero and it gets 11 degrees colder, the temperature is = - 49 degrees, not - 27
-12+(-10) NO - 34 - (-10) = - 34 + 10
-22 NO -24
this is what I got but text says the answer should be -24 And the text is correct. You made two errors that almost offset so your getting an answer that was close to right was pure luck. I AM SURE you can do this problem, but you need to be careful.