What is the sum of odd numbers from 121 to 190? Here we will show you step-by-step how to calculate the sum of odd numbers from 121 to 190.
Step 1) We start by finding the first (F) and last (L) odd numbers from 121 to 190. It is easy to do that by simply looking at the numbers. The first odd number is 121, and the last odd number is 189.
F = 121
L = 189
Step 2) Next, we calculate the total odd numbers (T) there are from 121 to 190, using a formula. Here is the formula and the math:
T = (L - F + 2) ÷ 2
T = (189 - 121 + 2) ÷ 2
T = 70 ÷ 2
T = 35
Step 3) Finally, we use the information from Step 1 and Step 2, and another formula, to calculate the sum of odd numbers from 121 to 190, like this:
Sum = (T ÷ 2) × (2 × F + (2 × (T - 1))
Sum = (35 ÷ 2) × (2 × 121 + (2 × (35 - 1))
Sum = 17.5 × (242 + 68)
Sum = 17.5 × 310
Sum = 5425
Sum of odd numbers from 121 to 190 = 5425
Sum of Odd Numbers Calculator
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