What is the sum of even numbers from 18 to 79? Here we will show you step-by-step how to calculate the sum of even numbers from 18 to 79.
Step 1) We start by finding the first (F) and last (L) even numbers from 18 to 79. It is easy to do that by simply looking at the numbers. The first even number is 18, and the last even number is 78.
F = 18
L = 78
Step 2) Next, we calculate the total even numbers (T) there are from 18 to 79, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (78 - 18 + 2) ÷ 2
T = 62 ÷ 2
T = 31
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 79, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (31 ÷ 2) × (2 × 18 + (2 × (31 - 1))
Sum = 15.5 × (36 + 60)
Sum = 15.5 × 96
Sum = 1488
Sum of even numbers from 18 to 79 = 1488
Sum of Even Numbers Calculator
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