why are the answers different when you add and subtract the same number

Question

i need help on this question, it is on my assignment, but i do not know someone please help

Answer 1

A tutor wrote:

 

 

(1) When a number is added to another number, it increases.

This is true ONLY IF the number added is positive.

(2) When a number is subtracted from another number, it decreases.

This is true ONLY IF the number being subtracted is positive.

 

 

examples: 5 + (-3) = 2   ... addition; result is decrease (from 5 to 2)

    6 - (-4) = 10    ...  subtraction; result is increase (from 6 to 10)

Answer 2

When a number is added to another number, it increases.

When a number is subtracted from another number, it decreases.

If two students are added to your class, it increases.

If two students leave (are subtracted) your class, it decreases.