What is the sum of even numbers from 19 to 138? Here we will show you step-by-step how to calculate the sum of even numbers from 19 to 138.
Step 1) We start by finding the first (F) and last (L) even numbers from 19 to 138. It is easy to do that by simply looking at the numbers. The first even number is 20, and the last even number is 138.
F = 20
L = 138
Step 2) Next, we calculate the total even numbers (T) there are from 19 to 138, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (138 - 20 + 2) ÷ 2
T = 120 ÷ 2
T = 60
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of even numbers from 19 to 138, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (60 ÷ 2) × (2 × 20 + (2 × (60 - 1))
Sum = 30 × (40 + 118)
Sum = 30 × 158
Sum = 4740
Sum of even numbers from 19 to 138 = 4740
Sum of Even Numbers Calculator
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