What is the sum of odd numbers from 8 to 25? Here we will show you step-by-step how to calculate the sum of odd numbers from 8 to 25.
Step 1) We start by finding the first (F) and last (L) odd numbers from 8 to 25. It is easy to do that by simply looking at the numbers. The first odd number is 9, and the last odd number is 25.
F = 9
L = 25
Step 2) Next, we calculate the total odd numbers (T) there are from 8 to 25, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (25 - 9 + 2) ÷ 2
T = 18 ÷ 2
T = 9
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 25, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (9 ÷ 2) × (2 × 9 + (2 × (9 - 1))
Sum = 4.5 × (18 + 16)
Sum = 4.5 × 34
Sum = 153
Sum of odd numbers from 8 to 25 = 153
Sum of Odd Numbers Calculator
Please use the tool below to calculate the sum of odd numbers for another set of numbers.