What is the sum of odd numbers from 20 to 127? Here we will show you step-by-step how to calculate the sum of odd numbers from 20 to 127.
Step 1) We start by finding the first (F) and last (L) odd numbers from 20 to 127. It is easy to do that by simply looking at the numbers. The first odd number is 21, and the last odd number is 127.
F = 21
L = 127
Step 2) Next, we calculate the total odd numbers (T) there are from 20 to 127, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (127 - 21 + 2) ÷ 2
T = 108 ÷ 2
T = 54
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of odd numbers from 20 to 127, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (54 ÷ 2) × (2 × 21 + (2 × (54 - 1))
Sum = 27 × (42 + 106)
Sum = 27 × 148
Sum = 3996
Sum of odd numbers from 20 to 127 = 3996
Sum of Odd Numbers Calculator
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