Since 8 is 23 and 81 is 34, the least common denominator is 23 x 34 = 648.
4536
The least common multiple of 58 and 81 is 4698. To find the least common multiple of big numbers, take 1/(number 1)+1/(number 2), then find a common denominator, then add them together and reduce. The denominator of this reduced fraction is the least common multiple. In this example, 1/58+1/81=81/4698+58/4698=139/4698, which does not reduce so 4698 is the least common multiple.
Convert both to decimal, and compare. For example, divide 81 / 105, and write down the decimal equivalent; the same for the other fraction. OR: Find a common denominator, and convert both to the common denominator. It need not be the least common denominator; any common denominator will do - for example, if you multiply 105 x 300, you have a common denominator (which is not the least common denominator in this case). The decimal method is much easier, by the way.
common denominator of eight and nine
There can be no greatest common denominator. If you have a set a numbers whose least common denominator is L then 2*L, 3*L, … are all common denominators. There is no end to that sequence and so no greatest.
8100
3
Their product.
Assuming that least common refers to the least common multiple, LCM(27, 81) = 81
The Least Common Multiple of 9 and 81 is 81.
the number 9