There is only one number that's equal to 81. That number is 81.
There are many other sets of two or more numbers that you can manipulate
with an arithmetic operation and produce 81 as the result. For example:
Addition: 27 + 54 = 81
Subtraction: 175 - 94 = 81
Multiplication: 3 x 27 = 81
Division: 567 / 7 = 81
But none of those other numbers is "equal" to 81.
1 x 81 3 x 27 9 x 9
3 * 27
There are no two real numbers that will add to -9 and multiply to 81. Using complex numbers, the two numbers are: (-9/2 + i9/2√3) and (-9/2 - i9/2√3)
1 and 81 Those two numbers certainly divide into 81 though they are not the only numbers to do so.
They are: 9 times 9 = 81
2.4115 and 33.5885 (to 4 dp)
1 x 243, 3 x 81, 9 x 27
1 x 6561, 3 x 2187, 9 x 729, 27 x 243, 81 x 81.
79 and 2 if you add them.
1 x 81, 3 x 27, 9 x 9.
81 = 1 x 81, 3 x 27, 9 x 9, 27 x 3, 81 x 1.
1 x 81, 3 x 27, 9 x 9