Let's divide 21587413 by 25
The aim is to understand the frequency of 25 in 21587413.

Step 1:
When dividing 2 by 25, we get 0 with a remainder of 2.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtracting 0 from 2 leaves us with 2.
Append the next digit (1) from the dividend to 2 and continue with: 21 / 25

Step 2:
If we divide 21 by 25, we get 0 and a remainder of 21.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 21 leaves us with 21.
Grab the next digit (5) from the dividend, add it to 21, then carry on: 215 / 25

Moving on to step 3:
The number 25 fits into 215 8 times, leaving a remainder of 15.
Write down 8 as next digit of the result. 
Result so far: 8.0
The remainder is 15 after subtracting 200 from 215.
Append the next digit (8) from the dividend to 15 and continue with: 158 / 25

Step 4:
If we divide 158 by 25, we get 6 and a remainder of 8.
The number 6 becomes the next digit in our result. 
Result so far: 86.0
Subtracting 150 from 158 leaves us with 8.
Append the next digit (7) from the dividend to 8 and continue with: 87 / 25

On to step 5:
The number 25 fits into 87 3 times, leaving a remainder of 12.
The number 3 becomes the next digit in our result. 
Result so far: 863.0
Subtract 75 from 87 to get 12.
Take the next digit (4) from the dividend and append it to 12, then repeat: 124 / 25

Moving on to step 6:
124 divided by 25 is 4 with a remainder of 24.
Use 4 as the next digit of our solution. 
Result so far: 8634.0
Deduct 100 from 124 and we're left with 24.
Bring next digit (1) of the dividend behind the 24 and repeat the process: 241 / 25

Step 7:
When dividing 241 by 25, we get 9 with a remainder of 16.
The number 9 becomes the next digit in our result. 
Result so far: 86349.0
Deduct 225 from 241 and we're left with 16.
Bring next digit (3) of the dividend behind the 16 and repeat the process: 163 / 25

Moving on to step 8:
If we divide 163 by 25, we get 6 and a remainder of 13.
Use 6 as the next digit of our solution. 
Result so far: 863496.0
If we take 150 away from 163, we end up with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Going ahead to step 9:
130 divided by 25 is 5 with a remainder of 5.
The number 5 becomes the next digit in our result. 
Result so far: 863496.5
Subtracting 125 from 130 leaves us with 5.
Since there are no more digits in the dividend, we add a zero to the remainder making it 50, and continue the process.

Advancing to step 10:
If we divide 50 by 25, we get 2 and a remainder of 0.
Put 2 as the next digit of the answer. 
Result so far: 863496.52
If we take 50 away from 50, 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.

Advancing to step 11:
0 divided by 25 is 0 with a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 863496.52
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.

Step 12:
25 can be fit into 0 0 times, resulting in a remainder of 0.
Write down 0 as next digit of the result. 
Result so far: 863496.52
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.

After the division, we end up with 863496.52 and a remainder of 0.0.