## Thinking Mathematically (6th Edition)

$1$ year
A person who frequently feels stretched will shrink his/her lifespan by 5 years. The number that represents this is $-5$. A person who has less than 12 years of education shrinks his/her lifespan by 6 years. The number that represents this is $-6$. Thus, the difference between the lifespan of the two is: $=-5 - (-6) = -5+6=1$ year