Use what you have found above to describe a quick way of adding up the first 20 add number answer in short and in number

Answer 1

To quickly add up the first 20 odd numbers, you can use the formula for the sum of an arithmetic series: S = n/2 * (2a + (n-1)d), where S is the sum, n is the number of terms, a is the first term, and d is the common difference. In this case, n = 20, a = 1, and d = 2 (since we are adding odd numbers). Plugging in these values, we get: S = 20/2 * (2*1 + (20-1)*2) = 10 * (2 + 38) = 10 * 40 = 400. Therefore, the sum of the first 20 odd numbers is 400.