661423 divided by 678 
The aim is to understand the frequency of 678 in 661423.

Advancing to step 1:
678 goes into 6 0 times with a remainder of 6.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Take the next digit (6) from the dividend and append it to 6, then repeat: 66 / 678

Step 2:
The number 678 fits into 66 0 times, leaving a remainder of 66.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 66 and we're left with 66.
Append the next digit (1) from the dividend to 66 and continue with: 661 / 678

Step 3:
678 goes into 661 0 times with a remainder of 661.
Write down 0 as next digit of the result. 
Result so far: 0.0
The remainder is 661 after subtracting 0 from 661.
Include the next digit (4) from the dividend after 661, then repeat: 6614 / 678

Step 4:
6614 divided by 678 is 9 with a remainder of 512.
Write down 9 as next digit of the result. 
Result so far: 9.0
If we take 6102 away from 6614, we end up with 512.
Append the next digit (2) from the dividend to 512 and continue with: 5122 / 678

Moving on to step 5:
The number 678 fits into 5122 7 times, leaving a remainder of 376.
Use 7 as the next digit of our solution. 
Result so far: 97.0
If we take 4746 away from 5122, we end up with 376.
Append the next digit (3) from the dividend to 376 and continue with: 3763 / 678

Step 6:
678 goes into 3763 5 times with a remainder of 373.
The number 5 becomes the next digit in our result. 
Result so far: 975.0
The remainder is 373 after subtracting 3390 from 3763.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3730, and continue the process.

Advancing to step 7:
When dividing 3730 by 678, we get 5 with a remainder of 340.
Record the quotient 5 as the next digit in the result. 
Result so far: 975.5
Deduct 3390 from 3730 and we're left with 340.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3400, and continue the process.

Moving on to step 8:
The number 678 fits into 3400 5 times, leaving a remainder of 10.
The next digit of our result is 5. 
Result so far: 975.55
If we take 3390 away from 3400, we end up with 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The final result is 975.55 with a remainder of 0.01.