What is the sum of even numbers from 3 to 40? Here we will show you step-by-step how to calculate the sum of even numbers from 3 to 40.
Step 1) We start by finding the first (F) and last (L) even numbers from 3 to 40. It is easy to do that by simply looking at the numbers. The first even number is 4, and the last even number is 40.
F = 4
L = 40
Step 2) Next, we calculate the total even numbers (T) there are from 3 to 40, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (40 - 4 + 2) ÷ 2
T = 38 ÷ 2
T = 19
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of even numbers from 3 to 40, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (19 ÷ 2) × (2 × 4 + (2 × (19 - 1))
Sum = 9.5 × (8 + 36)
Sum = 9.5 × 44
Sum = 418
Sum of even numbers from 3 to 40 = 418
Sum of Even Numbers Calculator
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