If Anna used 5/8 of the bucket and Glen used 1/4 of the bucket, then the total amount of clay used is:
5/8 + 1/4 = 10/16 + 4/16 = 14/16 = 7/8
Therefore, there is 1 - 7/8 = 1/8 of the bucket of clay left.
If we assume that the bucket is full, then the amount of clay left in the bucket is:
1/8 x the capacity of the bucket
We don't know the capacity of the bucket, so we can't give an exact answer. But if we assume that the bucket is a standard size, we can estimate that there are about 2-3 ounces of clay left in the bucket.