To find the sum of the first 81 odd numbers, we can use the formula for the sum of an arithmetic series: Sn = n/2 * (2a + (n-1)d), where n is the number of terms, a is the first term, and d is the common difference. In this case, n = 81, a = 1 (first odd number), and d = 2 (since the difference between consecutive odd numbers is 2). Plugging these values into the formula, we get: S81 = 81/2 * (2(1) + (81-1)2) = 81/2 * (2 + 160) = 81/2 * 162 = 6561. Therefore, the sum of the first 81 odd numbers is 6561.
To find the 9 odd numbers whose sum is 50 from 1 to 50, we can first calculate the sum of all odd numbers from 1 to 50, which is (50^2)/2 = 625. Next, we subtract the sum of the first 9 odd numbers (1+3+5+7+9+11+13+15+17 = 81) from the total sum, resulting in 625 - 81 = 544. Therefore, the 9 odd numbers whose sum is 50 from 1 to 50 are 19, 21, 23, 25, 27, 29, 31, 33, and 36.
3, 5, 7, 9, ... , 81.
81 + 83 = 164
27 and 81 are the odd numbers. Since odd numbers are 1, 3, 5, 7 and 9, look at the last number and you will be able to tell if it's odd or even.
27 and 81
The sum of the first nine odd numbers is 81.
To find the 9 odd numbers whose sum is 50 from 1 to 50, we can first calculate the sum of all odd numbers from 1 to 50, which is (50^2)/2 = 625. Next, we subtract the sum of the first 9 odd numbers (1+3+5+7+9+11+13+15+17 = 81) from the total sum, resulting in 625 - 81 = 544. Therefore, the 9 odd numbers whose sum is 50 from 1 to 50 are 19, 21, 23, 25, 27, 29, 31, 33, and 36.
25 (25+27+29=81)
3, 5, 7, 9, ... , 81.
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 = 81
It is 80*81/2 = 3240
1680
35,13,33
yes 9 25 49 81 121 All odd numbers squared are odd numbers
They are: 79+2 = 81
x + (x+2) + (x+4) = 249 3x+6=249 3x=243 x=81 81, 83, and 85
81 + 83 = 164