18 + 81 = 99
81
-18
9n + 18 = 81 9n = 63 n = 7
18 + 36 + 45 + 9 + 9 + 54 + 27 + 72 + 81 = 351
x2 + 63
few errors in your title: 2 plus 4 = 6 6 plus 9 = 15 10 plus 25 = 35 18 + 81 = 99
6+6+6+(81-91)+1000; First add together the sixes 18+(81-91)+1000; Next we add the terms in parenthasis 18+(-10)+1000; Since we have a negative 10, we chang the sign to minus 18-10+1000; Now we subtract 18-10 8+1000; Finally, 1000+8 = 1008 1008
78 + 79 + 80 + 80 + 81 + 81 = 479
The factors of 18 are 1,2,3,6,9, and 18. The factors of 81 are 1,3,9,27, and 81.
Gee, I don't know. Let's check it out. If it is, then 18 x 18 = 81 . 18 x 18 = 324 Nope. 18 x 18 is not 81, so 18 is not a square root of 81.
18/81 = 2/9 (divide top and bottom by the hcf of 18 & 81 = 9)
4.5