At 6:00 A.M., the temperature was $-5{}^{°}F$. By 2:00 P.M., the temperature had risen.${22}^0\text{F}$What was the temperature at 2:00 P.M.?

Rule: The sum of any integer and its opposite is equal to zero.

Rule: Adding two positive integers always gives a positive integer; adding two negative integers always gives a negative integer.

Rule: To find the sum of a positive and a negative integer, take the absolute value of each integer and then subtract these values.

To add two numbers with the same sign, first add the two numbers then put their common sign before the answer.

To add two numbers with the opposite sign, subtract the smaller number from the bigger number. Then put the sign of the bigger number before the answer.

An example of addition is: 5 + 11 + 3 = 19.

Example: If a = 7 and b = 8, find the value of a + b and a – b

To evaluate the expressiona + b, substitute the value of a as 7 and the value of b as 8 and add the numbers as shown below,$a+b=7+8=15$

and$a-b=7-8=-1$

To add two integers, we need to check the signs of those two integers.

Rule:To add two numbers with the opposite sign, ignore their signs and subtract the smaller number from the bigger number. Then put the sign of the bigger number before the answer.

The temperature at a particular time, given the temperature at an earlier time and the change in temperature between those two times

The temperature at $6:00AMis$$-5^{o}F$a particular time, given the temperature at an earlier time and the change in temperature between those two times

The temperature at 6:00 AM is and the increase in temperature up to 2:00 PM is${22}^{o}F$.

Rule: To find the temperature at a later time, add the change in temperature between the two times to the temperature at the earlier time.

The temperature at 2:00 PM is the sum of the temperature at 6:00 AM and the change in temperature between 6:00 AM and 2:00PM.

So, the temperature at 2:00 PM is$-5^{o}F+{22}^{o}F={17}^0\text{\hspace{0.17em}F.}$