15920740 ÷ 645 
We're looking to find how many times 645 goes into 15920740.

Step 1:
If we divide 1 by 645, we get 0 and a remainder of 1.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 1 leaves us with 1.
Include the next digit (5) from the dividend after 1, then repeat: 15 / 645

Let's proceed to step 2:
When dividing 15 by 645, we get 0 with a remainder of 15.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtract 0 from 15 to get 15.
Bring next digit (9) of the dividend behind the 15 and repeat the process: 159 / 645

Let's proceed to step 3:
159 divided by 645 is 0 with a remainder of 159.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 159 to get 159.
Include the next digit (2) from the dividend after 159, then repeat: 1592 / 645

On to step 4:
When dividing 1592 by 645, we get 2 with a remainder of 302.
The next digit of our result is 2. 
Result so far: 2.0
Subtracting 1290 from 1592 leaves us with 302.
Fetch the next digit (0) from the dividend, attach it to 302 and continue: 3020 / 645

Let's proceed to step 5:
3020 divided by 645 is 4 with a remainder of 440.
The next digit of our result is 4. 
Result so far: 24.0
If we take 2580 away from 3020, we end up with 440.
Fetch the next digit (7) from the dividend, attach it to 440 and continue: 4407 / 645

Step 6:
645 goes into 4407 6 times with a remainder of 537.
The number 6 becomes the next digit in our result. 
Result so far: 246.0
The remainder is 537 after subtracting 3870 from 4407.
Take the next digit (4) from the dividend and append it to 537, then repeat: 5374 / 645

Moving on to step 7:
645 can be fit into 5374 8 times, resulting in a remainder of 214.
Put 8 as the next digit of the answer. 
Result so far: 2468.0
Deduct 5160 from 5374 and we're left with 214.
Take the next digit (0) from the dividend and append it to 214, then repeat: 2140 / 645

Moving on to step 8:
645 goes into 2140 3 times with a remainder of 205.
Use 3 as the next digit of our solution. 
Result so far: 24683.0
Deduct 1935 from 2140 and we're left with 205.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2050, and continue the process.

Let's proceed to step 9:
If we divide 2050 by 645, we get 3 and a remainder of 115.
The next digit of our result is 3. 
Result so far: 24683.3
If we subtract 1935 from 2050, we get 115.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1150, and continue the process.

Advancing to step 10:
When dividing 1150 by 645, we get 1 with a remainder of 505.
Put 1 as the next digit of the answer. 
Result so far: 24683.31
Deduct 645 from 1150 and we're left with 505.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5050, and continue the process.

Moving on to step 11:
When dividing 5050 by 645, we get 7 with a remainder of 535.
Put 7 as the next digit of the answer. 
Result so far: 24683.317
If we subtract 4515 from 5050, we get 535.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5350, and continue the process.

Moving on to step 12:
5350 divided by 645 is 8 with a remainder of 190.
Record the quotient 8 as the next digit in the result. 
Result so far: 24683.3178
The remainder is 190 after subtracting 5160 from 5350.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1900, and continue the process.

Going ahead to step 13:
645 can be fit into 1900 2 times, resulting in a remainder of 610.
The next digit of our result is 2. 
Result so far: 24683.31782
Subtract 1290 from 1900 to get 610.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6100, and continue the process.

Step 14:
645 goes into 6100 9 times with a remainder of 295.
The number 9 becomes the next digit in our result. 
Result so far: 24683.317829
Subtracting 5805 from 6100 leaves us with 295.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2950, and continue the process.

On to step 15:
The number 645 fits into 2950 4 times, leaving a remainder of 370.
Use 4 as the next digit of our solution. 
Result so far: 24683.3178294
If we subtract 2580 from 2950, we get 370.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3700, and continue the process.

Moving on to step 16:
645 goes into 3700 5 times with a remainder of 475.
The next digit of our result is 5. 
Result so far: 24683.31782945
If we take 3225 away from 3700, we end up with 475.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4750, and continue the process.

Our division results in 24683.31782945 with a remaining 4.75e-07.