What is the sum of even numbers from 13 to 85? Here we will show you step-by-step how to calculate the sum of even numbers from 13 to 85.
Step 1) We start by finding the first (F) and last (L) even numbers from 13 to 85. It is easy to do that by simply looking at the numbers. The first even number is 14, and the last even number is 84.
F = 14
L = 84
Step 2) Next, we calculate the total even numbers (T) there are from 13 to 85, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (84 - 14 + 2) ÷ 2
T = 72 ÷ 2
T = 36
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of even numbers from 13 to 85, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (36 ÷ 2) × (2 × 14 + (2 × (36 - 1))
Sum = 18 × (28 + 70)
Sum = 18 × 98
Sum = 1764
Sum of even numbers from 13 to 85 = 1764
Sum of Even Numbers Calculator
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