Lowest terms means you can't simplify it anymore.
For example, if you have 4/10 thay can be simplified. All you have to do is look for a factor that fits easy one
4/10
A "2" divides equally into them
4 divided by 2 = 2
10 divided by 2 = 5
but nothing goes into 2 except 1 and 2, but neither 1 nor 2 into 5 evenly, so your fully simplified
some rules:
things ending 0 are always divisible by 10 (ans 5)
things ending in 0 ans 5 are always dividible by 5
things ending in even numbers are always divisible by 2
I believe if all the digits added up to a multiple of 3 that the number is divisible by 3 but I'm not sure
Do the same thing and you will know if it is or not in it's lowest terms.
Hope this helps. :)