37510809 ÷ 646 
The aim is to understand the frequency of 646 in 37510809.

On to step 1:
When dividing 3 by 646, we get 0 with a remainder of 3.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtracting 0 from 3 leaves us with 3.
Include the next digit (7) from the dividend after 3, then repeat: 37 / 646

Let's proceed to step 2:
When dividing 37 by 646, we get 0 with a remainder of 37.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 37 and we're left with 37.
Take the next digit (5) from the dividend and append it to 37, then repeat: 375 / 646

Advancing to step 3:
646 goes into 375 0 times with a remainder of 375.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 375 and we're left with 375.
Include the next digit (1) from the dividend after 375, then repeat: 3751 / 646

Advancing to step 4:
646 goes into 3751 5 times with a remainder of 521.
Record the quotient 5 as the next digit in the result. 
Result so far: 5.0
The remainder is 521 after subtracting 3230 from 3751.
Take the next digit (0) from the dividend and append it to 521, then repeat: 5210 / 646

Step 5:
When dividing 5210 by 646, we get 8 with a remainder of 42.
The next digit of our result is 8. 
Result so far: 58.0
The remainder is 42 after subtracting 5168 from 5210.
Bring next digit (8) of the dividend behind the 42 and repeat the process: 428 / 646

On to step 6:
When dividing 428 by 646, we get 0 with a remainder of 428.
Write down 0 as next digit of the result. 
Result so far: 580.0
If we subtract 0 from 428, we get 428.
Take the next digit (0) from the dividend and append it to 428, then repeat: 4280 / 646

Step 7:
4280 divided by 646 is 6 with a remainder of 404.
The number 6 becomes the next digit in our result. 
Result so far: 5806.0
The remainder is 404 after subtracting 3876 from 4280.
Fetch the next digit (9) from the dividend, attach it to 404 and continue: 4049 / 646

Advancing to step 8:
646 can be fit into 4049 6 times, resulting in a remainder of 173.
The number 6 becomes the next digit in our result. 
Result so far: 58066.0
Subtracting 3876 from 4049 leaves us with 173.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1730, and continue the process.

Advancing to step 9:
When dividing 1730 by 646, we get 2 with a remainder of 438.
Use 2 as the next digit of our solution. 
Result so far: 58066.2
Deduct 1292 from 1730 and we're left with 438.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4380, and continue the process.

Advancing to step 10:
646 can be fit into 4380 6 times, resulting in a remainder of 504.
The number 6 becomes the next digit in our result. 
Result so far: 58066.26
If we subtract 3876 from 4380, we get 504.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5040, and continue the process.

Going ahead to step 11:
5040 divided by 646 is 7 with a remainder of 518.
Record the quotient 7 as the next digit in the result. 
Result so far: 58066.267
If we subtract 4522 from 5040, we get 518.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5180, and continue the process.

Going ahead to step 12:
When dividing 5180 by 646, we get 8 with a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 58066.2678
If we take 5168 away from 5180, we end up with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

On to step 13:
If we divide 120 by 646, we get 0 and a remainder of 120.
Use 0 as the next digit of our solution. 
Result so far: 58066.2678
Subtract 0 from 120 to get 120.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1200, and continue the process.

Moving on to step 14:
The number 646 fits into 1200 1 times, leaving a remainder of 554.
The number 1 becomes the next digit in our result. 
Result so far: 58066.267801
Deduct 646 from 1200 and we're left with 554.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5540, and continue the process.

On to step 15:
If we divide 5540 by 646, we get 8 and a remainder of 372.
Record the quotient 8 as the next digit in the result. 
Result so far: 58066.2678018
Subtracting 5168 from 5540 leaves us with 372.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3720, and continue the process.

Advancing to step 16:
646 can be fit into 3720 5 times, resulting in a remainder of 490.
Put 5 as the next digit of the answer. 
Result so far: 58066.26780185
Deduct 3230 from 3720 and we're left with 490.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4900, and continue the process.

The final outcome is 58066.26780185, with a leftover of 4.9e-07.