explain how you can find the value of the expression -5+12+10-7

Question

explain how you can find the expression -5+12+10-5

 

Answer 1

Think of negative numbers as taking away dollars and positive numbers as getting paid some number of dollars.

 

-5 means you owe me 5 dollars

 

-5 + 12 means you owed my 5 dollars but you got paid 12 so once you pay me back you have 7 dollars. Then 

 

(-5+12) + 10

 

Well -5+12 we found was 7 dollars and now you just got 10 more so you must have 17 dollars. So -5+12+10=17

 

Finally we have

 

(-5+12+10) - 7 = 17 - 7

 

Well you have 17 dollars but now you owe me 7 so once you've paid that off you have 10 dollars left. So

 

-5 + 12 + 10 - 7 = 10