What is the sum of even numbers from 18 to 90? Here we will show you step-by-step how to calculate the sum of even numbers from 18 to 90.
Step 1) We start by finding the first (F) and last (L) even numbers from 18 to 90. It is easy to do that by simply looking at the numbers. The first even number is 18, and the last even number is 90.
F = 18
L = 90
Step 2) Next, we calculate the total even numbers (T) there are from 18 to 90, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (90 - 18 + 2) ÷ 2
T = 74 ÷ 2
T = 37
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 90, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (37 ÷ 2) × (2 × 18 + (2 × (37 - 1))
Sum = 18.5 × (36 + 72)
Sum = 18.5 × 108
Sum = 1998
Sum of even numbers from 18 to 90 = 1998
Sum of Even Numbers Calculator
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