Answer :
1 ) The number to be subtracted is called the subtrahend .
2 ) We know largest four digit number = 9999 , So
Number should be added to 4000 to get the largest 4 digit number = 9999 - 4000 = 5999 ( Ans )
3 ) We know largest four digit number = 9999 ,
And
Smallest four digit number = 1000
So ,
Number should be subtracted from the largest 4 digit number to get the smallest 4 digit number = 9999 - 1000 = 8999 ( Ans )