(X)y -> Number X with base y
For a number (r-1 r-1 r-1)r of radix 'r' . [Number of r-1 could be any here, I have limited to 3 as per question's demand]
eg- (111)2,(222)3,(333)4,(444)5,(555)6,(666)7,(777)8 ....etc
They represent (r-1)'s complement of 0 in their respective radix system.
Adding 1 to such numbers evaluates to r's complement of 0 in their respective radix system.
So the numbers are,
(1000)2,(1000)3,(1000)4,(1000)5,(1000)6,(1000)7,(1000)8 ....etc
Adding 1 more will just go to LSB(as r>1)
(1001)2,(1001)3,(1001)4,(1001)5,(1001)6,(1001)7,(1001)8 ....etc
The answer is (1000)5 , (1001)5 .