17.5
It is 2.5 more than 15 and 2.5 less than 20
To find a halfway point (which is also the average), add the numbers together and divide by 2.
It is (1.5 + 2.0)/2 = 1.75
The way to find an average (arithmetic mean) of two or more numbers is simple. Simply use the formula below.
sum of all the terms in a list / number of terms in the list
In the case of -15 and 20...
(-15) + 20 / 2 = 2.5
15
20
It is: 50
40
-5 It is 15 more than -20 and 15 less than 10 To find a halfway point (which is also the average), add the numbers together and divide by 2. -20 + 10 = -10 and -10/2 = -5
15
35
20
It is: 15
It is 20
It is: 50
17
-5
the number between 2 and 20 is 11
It is: (20+80)/2 = 50
40
30