We're dividing 641640 by 4 
The aim is to understand the frequency of 4 in 641640.

Advancing to step 1:
6 divided by 4 is 1 with a remainder of 2.
The next digit of our result is 1. 
Result so far: 1.0
If we take 4 away from 6, we end up with 2.
Append the next digit (4) from the dividend to 2 and continue with: 24 / 4

Step 2:
24 divided by 4 is 6 with a remainder of 0.
Put 6 as the next digit of the answer. 
Result so far: 16.0
Deduct 24 from 24 and we're left with 0.
Bring next digit (1) of the dividend behind the 0 and repeat the process: 1 / 4

Let's proceed to step 3:
4 can be fit into 1 0 times, resulting in a remainder of 1.
The number 0 becomes the next digit in our result. 
Result so far: 160.0
Deduct 0 from 1 and we're left with 1.
Bring next digit (6) of the dividend behind the 1 and repeat the process: 16 / 4

Let's proceed to step 4:
16 divided by 4 is 4 with a remainder of 0.
The number 4 becomes the next digit in our result. 
Result so far: 1604.0
If we subtract 16 from 16, we get 0.
Bring next digit (4) of the dividend behind the 0 and repeat the process: 4 / 4

Let's proceed to step 5:
4 can be fit into 4 1 times, resulting in a remainder of 0.
Write down 1 as next digit of the result. 
Result so far: 16041.0
If we take 4 away from 4, we end up with 0.
Grab the next digit (0) from the dividend, add it to 0, then carry on: 0 / 4

Step 6:
4 goes into 0 0 times with a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 160410.0
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 7:
If we divide 0 by 4, we get 0 and a remainder of 0.
The next digit of our result is 0. 
Result so far: 160410.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Advancing to step 8:
If we divide 0 by 4, we get 0 and a remainder of 0.
Put 0 as the next digit of the answer. 
Result so far: 160410.0
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 160410.0, with a leftover of 0.0.