In Closing The rules for adding and subtracting integers apply to all rational numbers. The sum of two rational numbers (e. g., −1 + 4.3) can be found on the number line by placing the tail of an arrow at −1 and locating the head of the arrow 4.3 units to the right to arrive at the sum, which is 3.3. To model the difference of two rational numbers on a number line (e. g., −5.7 − 3), first rewrite the difference as a sum, −5.7 +(−3), and then follow the steps for locating a sum. Place a single arrow with its tail at −5.7 and the head of the arrow 3 units to the left to arrive at −8.7.

(co 3) the times that customers spend in a book store are normally distributed with a mean of 39.5 minutes and a standard deviation of 9.4 minutes. a random sample of 25 customers has a mean of 36.1 minutes or less. would this outcome be considered unusual, so that the store should reconsider its displays? no, the probability of this outcome at 0.035, would be considered usual, so there is no problem yes, the probability of this outcome at 0.035, would be considered unusual, so the display should be redone no the probability of this outcome at 0.359 would be considered usual, so there is no problem yes, the probability of this outcome at 0.965 would be considered unusual, so the display should be redone