We look at the division of 48617510 by 645 
The aim is to understand the frequency of 645 in 48617510.

Going ahead to step 1:
The number 645 fits into 4 0 times, leaving a remainder of 4.
Put 0 as the next digit of the answer. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Grab the next digit (8) from the dividend, add it to 4, then carry on: 48 / 645

On to step 2:
645 can be fit into 48 0 times, resulting in a remainder of 48.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 48, we get 48.
Append the next digit (6) from the dividend to 48 and continue with: 486 / 645

Moving on to step 3:
645 goes into 486 0 times with a remainder of 486.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 486, we end up with 486.
Include the next digit (1) from the dividend after 486, then repeat: 4861 / 645

Step 4:
4861 divided by 645 is 7 with a remainder of 346.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
Subtracting 4515 from 4861 leaves us with 346.
Bring next digit (7) of the dividend behind the 346 and repeat the process: 3467 / 645

Moving on to step 5:
645 can be fit into 3467 5 times, resulting in a remainder of 242.
Record the quotient 5 as the next digit in the result. 
Result so far: 75.0
Subtracting 3225 from 3467 leaves us with 242.
Fetch the next digit (5) from the dividend, attach it to 242 and continue: 2425 / 645

Step 6:
When dividing 2425 by 645, we get 3 with a remainder of 490.
Use 3 as the next digit of our solution. 
Result so far: 753.0
The remainder is 490 after subtracting 1935 from 2425.
Append the next digit (1) from the dividend to 490 and continue with: 4901 / 645

Moving on to step 7:
The number 645 fits into 4901 7 times, leaving a remainder of 386.
The number 7 becomes the next digit in our result. 
Result so far: 7537.0
Deduct 4515 from 4901 and we're left with 386.
Bring next digit (0) of the dividend behind the 386 and repeat the process: 3860 / 645

Step 8:
645 can be fit into 3860 5 times, resulting in a remainder of 635.
Record the quotient 5 as the next digit in the result. 
Result so far: 75375.0
Deduct 3225 from 3860 and we're left with 635.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6350, and continue the process.

Advancing to step 9:
645 can be fit into 6350 9 times, resulting in a remainder of 545.
Write down 9 as next digit of the result. 
Result so far: 75375.9
Subtracting 5805 from 6350 leaves us with 545.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5450, and continue the process.

Let's proceed to step 10:
The number 645 fits into 5450 8 times, leaving a remainder of 290.
Use 8 as the next digit of our solution. 
Result so far: 75375.98
Deduct 5160 from 5450 and we're left with 290.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2900, and continue the process.

Moving on to step 11:
645 goes into 2900 4 times with a remainder of 320.
Record the quotient 4 as the next digit in the result. 
Result so far: 75375.984
Subtract 2580 from 2900 to get 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

On to step 12:
3200 divided by 645 is 4 with a remainder of 620.
The number 4 becomes the next digit in our result. 
Result so far: 75375.9844
Subtract 2580 from 3200 to get 620.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6200, and continue the process.

After the division, we end up with 75375.9844 and a remainder of 0.0062.