51213 ÷ 5 = 10242 R3
No problem, we've got 51213 and 5 for the division.

Step 1:
5 goes into 5 1 times with a remainder of 0.
Write down 1 as next digit of of the result. 
Result so far: 1
Subtract 5 from 5 to get 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 5

Step 2:
5 goes into 1 0 times with a remainder of 1.
Write down 0 as next digit of of the result. 
Result so far: 10
Subtract 0 from 1 to get 1.
Bring next digit (2) of the dividend behind the 1 and repeat the process: 12 / 5

Step 3:
5 goes into 12 2 times with a remainder of 2.
Write down 2 as next digit of of the result. 
Result so far: 102
Subtract 10 from 12 to get 2.
Bring next digit (1) of the dividend behind the 2 and repeat the process: 21 / 5

Step 4:
5 goes into 21 4 times with a remainder of 1.
Write down 4 as next digit of of the result. 
Result so far: 1024
Subtract 20 from 21 to get 1.
Bring next digit (3) of the dividend behind the 1 and repeat the process: 13 / 5

Step 5:
5 goes into 13 2 times with a remainder of 3.
Write down 2 as next digit of of the result. 
Result so far: 10242
Subtract 10 from 13 to get 3.

The final result is 10242 with a remainder of 3.