What is the sum of odd numbers from 10 to 61? Here we will show you step-by-step how to calculate the sum of odd numbers from 10 to 61.
Step 1) We start by finding the first (F) and last (L) odd numbers from 10 to 61. It is easy to do that by simply looking at the numbers. The first odd number is 11, and the last odd number is 61.
F = 11
L = 61
Step 2) Next, we calculate the total odd numbers (T) there are from 10 to 61, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (61 - 11 + 2) ÷ 2
T = 52 ÷ 2
T = 26
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of odd numbers from 10 to 61, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (26 ÷ 2) × (2 × 11 + (2 × (26 - 1))
Sum = 13 × (22 + 50)
Sum = 13 × 72
Sum = 936
Sum of odd numbers from 10 to 61 = 936
Sum of Odd Numbers Calculator
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