Missing number from the mean, step by step
Finding the mean shares a total out; this runs it backward.
The question
Missing number for a mean of 12
12 × 5=60
8 + 18 + 17 + 1 =44
60 − 44=16
- The mean is the total shared out evenly, so run it backward: 5 numbers with a mean of 12 must add up to 12 × 5 = 60.
- The numbers you already have add to 8 + 18 + 17 + 1 = 44.
- So the missing number is what is left to reach 60: 60 − 44 = 16.
How it works.
- 01
The mean is the total shared out evenly, so run it backward: 5 numbers with a mean of 12 must add up to 12 × 5 = 60.
- 02
The numbers you already have add to 8 + 18 + 17 + 1 = 44.
- 03
So the missing number is what is left to reach 60: 60 − 44 = 16.