Huh?

Don't worry Greg. I understand why you are confused. It is because you know your maths and this stupid piece of algebra took you to space and back for no reason.

So how can you have 45 as the common denominator for 4 and 5? It doesn't make sense does it. It can be 20, 40 or 60 but not 45. Correct! you cannot have 45 as the common denominator for 4 and 5.

1 on 4 times 8 on 5 is 8 on 20. 8 on 20 can be simplified to 2 over 5. Got it?

Now some silly bugger for some unknown reason happened to multiple 2 over 5 by 9. That gave you 18 on 45. Confusing isn't it? It is no worse than 6 / 15 I guess.


:D

I'm well aware of what I have typed. I don't have confusion at all unless it's with women.
What this is all about is that there is a small number (14) of groups of numbers where the multiplication of the numerator and denominators of two fractions provide a number equal to that of the same numbers when just placed together on the numerator and denominator.
It's good fun.

good night....
See you next weekend.
Greg

You don't need common denominators to multiply or divide fractions, as someone said.

You do need them to add or subtract frations.