What is the sum of odd numbers from 8 to 39? Here we will show you step-by-step how to calculate the sum of odd numbers from 8 to 39.
Step 1) We start by finding the first (F) and last (L) odd numbers from 8 to 39. It is easy to do that by simply looking at the numbers. The first odd number is 9, and the last odd number is 39.
F = 9
L = 39
Step 2) Next, we calculate the total odd numbers (T) there are from 8 to 39, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (39 - 9 + 2) ÷ 2
T = 32 ÷ 2
T = 16
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 39, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (16 ÷ 2) × (2 × 9 + (2 × (16 - 1))
Sum = 8 × (18 + 30)
Sum = 8 × 48
Sum = 384
Sum of odd numbers from 8 to 39 = 384
Sum of Odd Numbers Calculator
Please use the tool below to calculate the sum of odd numbers for another set of numbers.