53943 ÷ 4 = 13485 R3
No problem, we've got 53943 and 4 for the division.

Step 1:
4 goes into 5 1 times with a remainder of 1.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 4 from 5 to get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 4

Step 2:
4 goes into 13 3 times with a remainder of 1.
Write down 3 as next digit of of the result. 
Result so far: 13
Subtract 12 from 13 to get 1.
Bring next digit (9) of the dividend behind the 1 and repeat the process: 19 / 4

Step 3:
4 goes into 19 4 times with a remainder of 3.
Write down 4 as next digit of of the result. 
Result so far: 134
Subtract 16 from 19 to get 3.
Bring next digit (4) of the dividend behind the 3 and repeat the process: 34 / 4

Step 4:
4 goes into 34 8 times with a remainder of 2.
Write down 8 as next digit of of the result. 
Result so far: 1348
Subtract 32 from 34 to get 2.
Bring next digit (3) of the dividend behind the 2 and repeat the process: 23 / 4

Step 5:
4 goes into 23 5 times with a remainder of 3.
Write down 5 as next digit of of the result. 
Result so far: 13485
Subtract 20 from 23 to get 3.

The final result is 13485 with a remainder of 3.