What is the average of even numbers from 9 to 21? Here we will show you how to calculate the average of even numbers from 9 to 21.
To find the average of the even numbers from 9 to 21, we first calculate how many even numbers there are from 9 to 21. Then, we calculate the sum of even numbers from 9 to 21. And finally, we divide the sum by the number of even numbers to get the average.
The range is from 9 to 21, and the even numbers within that range are from 10 to 20. Therefore, the first even number in the sequence is 10, and the last even number in the sequence is 20.
Step 1) Calculate the total number of even numbers from 9 to 21
Here we calculate the total number of even numbers from 9 to 21 by entering the first and last even number in the sequence into our formula. Here is the formula and the math:
tot = (last - first + 2) ÷ 2
tot = (20 - 10 + 2) ÷ 2
tot = 12 ÷ 2
tot = 6
Total even numbers from 9 to 21 = 6
Step 2) Calculate the sum of even numbers from 9 to 21
To calculate the sum of even numbers from 9 to 21, you enter the total even numbers (tot) from Step 1 and the first even number in the sequence into our formula. Here is the formula and the math:
sum = (tot ÷ 2) × (2 × first + (2 × (tot - 1))
sum = (6 ÷ 2) × (2 × 10 + (2 × (6 - 1))
sum = 3 × (20 + 10)
sum = 3 × 30
sum = 90
Sum of even numbers from 9 to 21 = 90
Step 3) Calculate the average of even numbers from 9 to 21
Almost done! Now we can calculate the average of even numbers from 9 to 21 by dividing the sum of even numbers from Step 2 by the total even numbers from Step 1. Here is the formula, the math, and the answer:
Average = sum ÷ tot
Average = 90 ÷ 6
Average = 15
Average of even numbers from 9 to 21 = 15
Average of Even Numbers Calculator
Here you can calculate the average of even numbers of a different sequence.