25797991 ÷ 640 
The aim is to understand the frequency of 640 in 25797991.

Moving on to step 1:
640 can be fit into 2 0 times, resulting in a remainder of 2.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtract 0 from 2 to get 2.
Fetch the next digit (5) from the dividend, attach it to 2 and continue: 25 / 640

On to step 2:
640 goes into 25 0 times with a remainder of 25.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we take 0 away from 25, we end up with 25.
Take the next digit (7) from the dividend and append it to 25, then repeat: 257 / 640

Going ahead to step 3:
If we divide 257 by 640, we get 0 and a remainder of 257.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 257 after subtracting 0 from 257.
Take the next digit (9) from the dividend and append it to 257, then repeat: 2579 / 640

Moving on to step 4:
640 can be fit into 2579 4 times, resulting in a remainder of 19.
The next digit of our result is 4. 
Result so far: 4.0
The remainder is 19 after subtracting 2560 from 2579.
Fetch the next digit (7) from the dividend, attach it to 19 and continue: 197 / 640

Advancing to step 5:
The number 640 fits into 197 0 times, leaving a remainder of 197.
The next digit of our result is 0. 
Result so far: 40.0
If we subtract 0 from 197, we get 197.
Include the next digit (9) from the dividend after 197, then repeat: 1979 / 640

Let's proceed to step 6:
When dividing 1979 by 640, we get 3 with a remainder of 59.
Put 3 as the next digit of the answer. 
Result so far: 403.0
The remainder is 59 after subtracting 1920 from 1979.
Grab the next digit (9) from the dividend, add it to 59, then carry on: 599 / 640

Moving on to step 7:
When dividing 599 by 640, we get 0 with a remainder of 599.
The next digit of our result is 0. 
Result so far: 4030.0
If we take 0 away from 599, we end up with 599.
Grab the next digit (1) from the dividend, add it to 599, then carry on: 5991 / 640

On to step 8:
When dividing 5991 by 640, we get 9 with a remainder of 231.
The number 9 becomes the next digit in our result. 
Result so far: 40309.0
Deduct 5760 from 5991 and we're left with 231.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2310, and continue the process.

Let's proceed to step 9:
2310 divided by 640 is 3 with a remainder of 390.
Put 3 as the next digit of the answer. 
Result so far: 40309.3
Deduct 1920 from 2310 and we're left with 390.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3900, and continue the process.

Step 10:
640 can be fit into 3900 6 times, resulting in a remainder of 60.
Write down 6 as next digit of the result. 
Result so far: 40309.36
The remainder is 60 after subtracting 3840 from 3900.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Advancing to step 11:
The number 640 fits into 600 0 times, leaving a remainder of 600.
Use 0 as the next digit of our solution. 
Result so far: 40309.36
Subtracting 0 from 600 leaves us with 600.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6000, and continue the process.

Let's proceed to step 12:
When dividing 6000 by 640, we get 9 with a remainder of 240.
Use 9 as the next digit of our solution. 
Result so far: 40309.3609
Subtract 5760 from 6000 to get 240.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2400, and continue the process.

Advancing to step 13:
2400 divided by 640 is 3 with a remainder of 480.
Put 3 as the next digit of the answer. 
Result so far: 40309.36093
The remainder is 480 after subtracting 1920 from 2400.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4800, and continue the process.

Moving on to step 14:
The number 640 fits into 4800 7 times, leaving a remainder of 320.
Write down 7 as next digit of the result. 
Result so far: 40309.360937
If we take 4480 away from 4800, we end up with 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

Let's proceed to step 15:
The number 640 fits into 3200 5 times, leaving a remainder of 0.
Use 5 as the next digit of our solution. 
Result so far: 40309.3609375
Subtract 3200 from 3200 to 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.

Let's proceed to step 16:
640 goes into 0 0 times with a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 40309.3609375
If we take 0 away from 0, we end up 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 40309.3609375, with a leftover of 0.0.