We're dividing 6640960 by 258 
The aim is to understand the frequency of 258 in 6640960.

Moving on to step 1:
When dividing 6 by 258, we get 0 with a remainder of 6.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 6 leaves us with 6.
Grab the next digit (6) from the dividend, add it to 6, then carry on: 66 / 258

Advancing to step 2:
If we divide 66 by 258, we get 0 and a remainder of 66.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 66, we get 66.
Bring next digit (4) of the dividend behind the 66 and repeat the process: 664 / 258

On to step 3:
258 goes into 664 2 times with a remainder of 148.
The next digit of our result is 2. 
Result so far: 2.0
Deduct 516 from 664 and we're left with 148.
Take the next digit (0) from the dividend and append it to 148, then repeat: 1480 / 258

Let's proceed to step 4:
258 can be fit into 1480 5 times, resulting in a remainder of 190.
Put 5 as the next digit of the answer. 
Result so far: 25.0
The remainder is 190 after subtracting 1290 from 1480.
Bring next digit (9) of the dividend behind the 190 and repeat the process: 1909 / 258

Moving on to step 5:
When dividing 1909 by 258, we get 7 with a remainder of 103.
Record the quotient 7 as the next digit in the result. 
Result so far: 257.0
Deduct 1806 from 1909 and we're left with 103.
Append the next digit (6) from the dividend to 103 and continue with: 1036 / 258

Going ahead to step 6:
When dividing 1036 by 258, we get 4 with a remainder of 4.
Put 4 as the next digit of the answer. 
Result so far: 2574.0
If we take 1032 away from 1036, we end up with 4.
Bring next digit (0) of the dividend behind the 4 and repeat the process: 40 / 258

Step 7:
258 goes into 40 0 times with a remainder of 40.
The next digit of our result is 0. 
Result so far: 25740.0
Subtract 0 from 40 to get 40.
Since there are no more digits in the dividend, we add a zero to the remainder making it 400, and continue the process.

Moving on to step 8:
258 goes into 400 1 times with a remainder of 142.
Write down 1 as next digit of the result. 
Result so far: 25740.1
Deduct 258 from 400 and we're left with 142.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1420, and continue the process.

Advancing to step 9:
258 goes into 1420 5 times with a remainder of 130.
Record the quotient 5 as the next digit in the result. 
Result so far: 25740.15
If we subtract 1290 from 1420, we get 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Advancing to step 10:
If we divide 1300 by 258, we get 5 and a remainder of 10.
The next digit of our result is 5. 
Result so far: 25740.155
Deduct 1290 from 1300 and we're left 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 outcome is 25740.155, with a leftover of 0.001.