We look at the division of 46744653 by 645 
The aim is to understand the frequency of 645 in 46744653.

Let's proceed to step 1:
645 goes into 4 0 times with a remainder of 4.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Bring next digit (6) of the dividend behind the 4 and repeat the process: 46 / 645

Advancing to step 2:
645 can be fit into 46 0 times, resulting in a remainder of 46.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
The remainder is 46 after subtracting 0 from 46.
Include the next digit (7) from the dividend after 46, then repeat: 467 / 645

On to step 3:
When dividing 467 by 645, we get 0 with a remainder of 467.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 467, we end up with 467.
Grab the next digit (4) from the dividend, add it to 467, then carry on: 4674 / 645

On to step 4:
645 can be fit into 4674 7 times, resulting in a remainder of 159.
Put 7 as the next digit of the answer. 
Result so far: 7.0
If we take 4515 away from 4674, we end up with 159.
Take the next digit (4) from the dividend and append it to 159, then repeat: 1594 / 645

Advancing to step 5:
1594 divided by 645 is 2 with a remainder of 304.
Put 2 as the next digit of the answer. 
Result so far: 72.0
If we subtract 1290 from 1594, we get 304.
Grab the next digit (6) from the dividend, add it to 304, then carry on: 3046 / 645

On to step 6:
3046 divided by 645 is 4 with a remainder of 466.
Put 4 as the next digit of the answer. 
Result so far: 724.0
Deduct 2580 from 3046 and we're left with 466.
Include the next digit (5) from the dividend after 466, then repeat: 4665 / 645

Advancing to step 7:
If we divide 4665 by 645, we get 7 and a remainder of 150.
Write down 7 as next digit of the result. 
Result so far: 7247.0
If we subtract 4515 from 4665, we get 150.
Take the next digit (3) from the dividend and append it to 150, then repeat: 1503 / 645

Going ahead to step 8:
1503 divided by 645 is 2 with a remainder of 213.
Use 2 as the next digit of our solution. 
Result so far: 72472.0
Deduct 1290 from 1503 and we're left with 213.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2130, and continue the process.

Going ahead to step 9:
If we divide 2130 by 645, we get 3 and a remainder of 195.
Put 3 as the next digit of the answer. 
Result so far: 72472.3
Subtracting 1935 from 2130 leaves us with 195.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1950, and continue the process.

Advancing to step 10:
1950 divided by 645 is 3 with a remainder of 15.
The number 3 becomes the next digit in our result. 
Result so far: 72472.33
If we subtract 1935 from 1950, we get 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

After the division, we end up with 72472.33 and a remainder of 0.015.