How do you find the missing number when you have four numbers but missing the fifth. Find the average of 12.3 with the numbers of 12.8,12.6,11.8,9.7

5 * 12.3 = 61.5

That is the total of the 5 numbers with that average.

So, the missing number is 61.5 minus the sum of the first 4 numbers.

5 * 12.3 = 61.5

12.8 + 12.6 + 11.8 + 9.7 = 46.9

61.5 - 46.9 = 14.6

To find the missing number when you have four numbers and are missing the fifth, you can use the concept of the average.

Step 1: Add the four given numbers.
12.8 + 12.6 + 11.8 + 9.7 = 46.9

Step 2: Find the sum of the five numbers.
Let the missing number be x.
46.9 + x = Sum of all five numbers

Step 3: Multiply the average (12.3) by 5 to get the sum of all five numbers.
12.3 * 5 = 61.5

Step 4: Set up an equation to solve for x.
46.9 + x = 61.5

Step 5: Solve the equation for x.
x = 61.5 - 46.9
x = 14.6

Therefore, the missing number is 14.6.