42969250 ÷ 645 
We want to figure out the number of times 42969250 can be divided by 645.

On to step 1:
645 goes into 4 0 times with a remainder of 4.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 4 after subtracting 0 from 4.
Take the next digit (2) from the dividend and append it to 4, then repeat: 42 / 645

Going ahead to step 2:
645 goes into 42 0 times with a remainder of 42.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 42 and we're left with 42.
Grab the next digit (9) from the dividend, add it to 42, then carry on: 429 / 645

Advancing to step 3:
When dividing 429 by 645, we get 0 with a remainder of 429.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 429, we get 429.
Fetch the next digit (6) from the dividend, attach it to 429 and continue: 4296 / 645

Moving on to step 4:
The number 645 fits into 4296 6 times, leaving a remainder of 426.
The number 6 becomes the next digit in our result. 
Result so far: 6.0
Subtract 3870 from 4296 to get 426.
Fetch the next digit (9) from the dividend, attach it to 426 and continue: 4269 / 645

Advancing to step 5:
4269 divided by 645 is 6 with a remainder of 399.
Put 6 as the next digit of the answer. 
Result so far: 66.0
If we subtract 3870 from 4269, we get 399.
Grab the next digit (2) from the dividend, add it to 399, then carry on: 3992 / 645

Advancing to step 6:
3992 divided by 645 is 6 with a remainder of 122.
Put 6 as the next digit of the answer. 
Result so far: 666.0
Deduct 3870 from 3992 and we're left with 122.
Fetch the next digit (5) from the dividend, attach it to 122 and continue: 1225 / 645

Step 7:
645 goes into 1225 1 times with a remainder of 580.
Use 1 as the next digit of our solution. 
Result so far: 6661.0
Subtracting 645 from 1225 leaves us with 580.
Bring next digit (0) of the dividend behind the 580 and repeat the process: 5800 / 645

Step 8:
5800 divided by 645 is 8 with a remainder of 640.
The next digit of our result is 8. 
Result so far: 66618.0
If we take 5160 away from 5800, we end up with 640.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6400, and continue the process.

On to step 9:
The number 645 fits into 6400 9 times, leaving a remainder of 595.
Put 9 as the next digit of the answer. 
Result so far: 66618.9
Subtracting 5805 from 6400 leaves us with 595.
Since there are no more digits in the dividend, we add a zero to the remainder making it 5950, and continue the process.

Step 10:
645 can be fit into 5950 9 times, resulting in a remainder of 145.
The next digit of our result is 9. 
Result so far: 66618.99
Deduct 5805 from 5950 and we're left with 145.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1450, and continue the process.

The final outcome is 66618.99, with a leftover of 0.145.