We're dividing 668721 by 3 
The aim is to understand the frequency of 3 in 668721.

Moving on to step 1:
6 divided by 3 is 2 with a remainder of 0.
The next digit of our result is 2. 
Result so far: 2.0
Subtracting 6 from 6 leaves us with 0.
Grab the next digit (6) from the dividend, add it to 0, then carry on: 6 / 3

Going ahead to step 2:
The number 3 fits into 6 2 times, leaving a remainder of 0.
Record the quotient 2 as the next digit in the result. 
Result so far: 22.0
If we take 6 away from 6, we end up with 0.
Take the next digit (8) from the dividend and append it to 0, then repeat: 8 / 3

Step 3:
The number 3 fits into 8 2 times, leaving a remainder of 2.
The number 2 becomes the next digit in our result. 
Result so far: 222.0
Subtract 6 from 8 to get 2.
Append the next digit (7) from the dividend to 2 and continue with: 27 / 3

Going ahead to step 4:
27 divided by 3 is 9 with a remainder of 0.
Put 9 as the next digit of the answer. 
Result so far: 2229.0
The remainder is 0 after subtracting 27 from 27.
Take the next digit (2) from the dividend and append it to 0, then repeat: 2 / 3

Let's proceed to step 5:
2 divided by 3 is 0 with a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 22290.0
Subtracting 0 from 2 leaves us with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 3

Step 6:
If we divide 21 by 3, we get 7 and a remainder of 0.
Put 7 as the next digit of the answer. 
Result so far: 222907.0
Subtracting 21 from 21 leaves us 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 7:
0 divided by 3 is 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 222907.0
Subtracting 0 from 0 leaves us 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.

Going ahead to step 8:
When dividing 0 by 3, we get 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 222907.0
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Our division results in 222907.0 with a remaining 0.0.