Write the successor of 3879

Which is the smallest number when we arranged the numbers 4729,4374,4279,4972 in ascending order.

7000 + 200 + 30 + 1 = __________

7230_______4921

Smallest 4 digit number is

Which is the greatest number when we arrange the numbers 3976,3697,3977,3796 in descending order.

Five thousand,six hundred and twenty two = _________

Write the number comes between 6321 and 6323

2672,2673,________,2675

Write the greatest 4 digit number using digits 0,3,7,2