Integer greater than 40 and less than 60 and satisfying these two conditions.

Then the answers include: 4142 43 44 45 46 47 48 49 50 5152 53 54 55 56 57 58 59.

You can write: 4 1~59

Note that it is an integer, not an integer of ten.

There is a difference between the two.

If it is an integer of ten.

Then the answer is 50.