What is the sum of even numbers from 21 to 88? Here we will show you step-by-step how to calculate the sum of even numbers from 21 to 88.
Step 1) We start by finding the first (F) and last (L) even numbers from 21 to 88. It is easy to do that by simply looking at the numbers. The first even number is 22, and the last even number is 88.
F = 22
L = 88
Step 2) Next, we calculate the total even numbers (T) there are from 21 to 88, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (88 - 22 + 2) ÷ 2
T = 68 ÷ 2
T = 34
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of even numbers from 21 to 88, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (34 ÷ 2) × (2 × 22 + (2 × (34 - 1))
Sum = 17 × (44 + 66)
Sum = 17 × 110
Sum = 1870
Sum of even numbers from 21 to 88 = 1870
Sum of Even Numbers Calculator
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