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Sequences: Consecutive Integers - Calculating the Sum of Consecutive Integers

What is the sum of all consecutive multiples of 8 between 400 and 600, inclusive?
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Correct. [[Snippet]] Both 400 and 600 are multiples of 8, so use them as the first and last multiples in the range. First calculate the number of terms: 1. Subtract the extremes: >>$$600 - 400 = 200$$ 2. Divide by 8: >>$$\frac{200}{8} = 25$$ 3. Add 1: >>$$25 + 1 = 26$$ Then calculate the average: >$$\text{Average} = \frac{400 + 600}{ 2} = \frac{1{,}000}{2} = 500$$ Finally, multiply the number of terms by the average: >$$\text{Sum} = 26 \times 500 = 13{,}000$$
8,000
10,400
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