What is the sum of even numbers from 3 to 15? Here we will show you step-by-step how to calculate the sum of even numbers from 3 to 15.
Step 1) We start by finding the first (F) and last (L) even numbers from 3 to 15. It is easy to do that by simply looking at the numbers. The first even number is 4, and the last even number is 14.
F = 4
L = 14
Step 2) Next, we calculate the total even numbers (T) there are from 3 to 15, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (14 - 4 + 2) ÷ 2
T = 12 ÷ 2
T = 6
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of even numbers from 3 to 15, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (6 ÷ 2) × (2 × 4 + (2 × (6 - 1))
Sum = 3 × (8 + 10)
Sum = 3 × 18
Sum = 54
Sum of even numbers from 3 to 15 = 54
Sum of Even Numbers Calculator
Please use the tool below to calculate the sum of even numbers for another set of numbers.