315
9
The least common denominator (LCD) is 630.
315.
All those numbers are mutually prime (5 and 7 are prime, full stop), so the least common denominator is 5x7x8x9.
63
It is 630
The lowest common denominator of any set of whole numbers is 1
It is: 3465 which is also their LCM
To subtract fractions, you need a common denominator. In this case, the common denominator is 45. So, 7/9 - 1/5 is equal to (35/45) - (9/45), which simplifies to 26/45.
36
63
A common denominator, though not the least, is 63000.