What is the sum of odd numbers from 8 to 38? Here we will show you step-by-step how to calculate the sum of odd numbers from 8 to 38.
Step 1) We start by finding the first (F) and last (L) odd numbers from 8 to 38. It is easy to do that by simply looking at the numbers. The first odd number is 9, and the last odd number is 37.
F = 9
L = 37
Step 2) Next, we calculate the total odd numbers (T) there are from 8 to 38, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (37 - 9 + 2) ÷ 2
T = 30 ÷ 2
T = 15
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of odd numbers from 8 to 38, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (15 ÷ 2) × (2 × 9 + (2 × (15 - 1))
Sum = 7.5 × (18 + 28)
Sum = 7.5 × 46
Sum = 345
Sum of odd numbers from 8 to 38 = 345
Sum of Odd Numbers Calculator
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