3. Make the greatest and the smallest 4-digit numbers using any four different digits with conditions as given.
(a) Digit 7 is always at one's place
Greatest - 9 8 6 7
Smallest - 1 0 2 7
(Note, the number cannot begin with the digit 0. Why?)
(b) Digit 4 is always at tens place
Greatest - _ _ 4 _
Smallest - _ _ 4 _
(c) Digit 9 is always at hundreds place
Greatest - _ 9 _ _
Smallest - _ 9 _ _
(d) Digit 1 is always at thousands place
Greatest- 1 _ _ _
Smallest - 1 _ _ _
(b) Digit 4 is always at tens place
Greatest - 9847
Smallest - 1042
(c) Digit 9 is always at hundreds place
Greatest - 8976
Smallest - 1902
(d) Digit 1 is always at thousands place
Greatest- 1987
Smallest - 1023