What is the sum of even numbers from 18 to 42? Here we will show you step-by-step how to calculate the sum of even numbers from 18 to 42.
Step 1) We start by finding the first (F) and last (L) even numbers from 18 to 42. It is easy to do that by simply looking at the numbers. The first even number is 18, and the last even number is 42.
F = 18
L = 42
Step 2) Next, we calculate the total even numbers (T) there are from 18 to 42, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (42 - 18 + 2) ÷ 2
T = 26 ÷ 2
T = 13
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of even numbers from 18 to 42, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (13 ÷ 2) × (2 × 18 + (2 × (13 - 1))
Sum = 6.5 × (36 + 24)
Sum = 6.5 × 60
Sum = 390
Sum of even numbers from 18 to 42 = 390
Sum of Even Numbers Calculator
Please use the tool below to calculate the sum of even numbers for another set of numbers.