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.
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.
The integers are 81, 83, 85 and 87.
27 and 81
The sum of the first nine odd numbers is 81.
3, 5, 7, 9, ... , 81.
25 (25+27+29=81)
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 = 81
It is 80*81/2 = 3240
35,13,33
1680
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
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.