How can I find the missing number with the mean and total numbers?

Answer 1

The mean is the average of a group of numbers. It's obtained by adding all the numbers up and dividing by the number of numbers.

Mean = (sum of numbers) / (number of numbers)

(Mean)x(number of numbers) = (sum of numbers)

The sum of numbers would be the total of the numbers you were given plus the one that you don't have.

(Mean)x(number of numbers) = (sum of numbers you know + unknown number)

(Mean)x(number of numbers) - (sum of numbers you know) = unknown number

Hope this helps :)