We're dividing 61515345 by 90 
We want to figure out the number of times 61515345 can be divided by 90.

Advancing to step 1:
If we divide 6 by 90, we get 0 and a remainder of 6.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we take 0 away from 6, we end up with 6.
Take the next digit (1) from the dividend and append it to 6, then repeat: 61 / 90

Moving on to step 2:
61 divided by 90 is 0 with a remainder of 61.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtracting 0 from 61 leaves us with 61.
Fetch the next digit (5) from the dividend, attach it to 61 and continue: 615 / 90

Let's proceed to step 3:
The number 90 fits into 615 6 times, leaving a remainder of 75.
The next digit of our result is 6. 
Result so far: 6.0
Subtracting 540 from 615 leaves us with 75.
Bring next digit (1) of the dividend behind the 75 and repeat the process: 751 / 90

On to step 4:
If we divide 751 by 90, we get 8 and a remainder of 31.
Put 8 as the next digit of the answer. 
Result so far: 68.0
Subtracting 720 from 751 leaves us with 31.
Bring next digit (5) of the dividend behind the 31 and repeat the process: 315 / 90

Advancing to step 5:
90 can be fit into 315 3 times, resulting in a remainder of 45.
Record the quotient 3 as the next digit in the result. 
Result so far: 683.0
Subtract 270 from 315 to get 45.
Grab the next digit (3) from the dividend, add it to 45, then carry on: 453 / 90

On to step 6:
90 goes into 453 5 times with a remainder of 3.
Put 5 as the next digit of the answer. 
Result so far: 6835.0
Subtracting 450 from 453 leaves us with 3.
Take the next digit (4) from the dividend and append it to 3, then repeat: 34 / 90

Let's proceed to step 7:
When dividing 34 by 90, we get 0 with a remainder of 34.
Use 0 as the next digit of our solution. 
Result so far: 68350.0
Subtracting 0 from 34 leaves us with 34.
Fetch the next digit (5) from the dividend, attach it to 34 and continue: 345 / 90

Step 8:
If we divide 345 by 90, we get 3 and a remainder of 75.
Use 3 as the next digit of our solution. 
Result so far: 683503.0
Deduct 270 from 345 and we're left with 75.
Since there are no more digits in the dividend, we add a zero to the remainder making it 750, and continue the process.

Going ahead to step 9:
If we divide 750 by 90, we get 8 and a remainder of 30.
Put 8 as the next digit of the answer. 
Result so far: 683503.8
Subtract 720 from 750 to get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Going ahead to step 10:
When dividing 300 by 90, we get 3 with a remainder of 30.
The number 3 becomes the next digit in our result. 
Result so far: 683503.83
Deduct 270 from 300 and we're left with 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

Going ahead to step 11:
When dividing 300 by 90, we get 3 with a remainder of 30.
The number 3 becomes the next digit in our result. 
Result so far: 683503.833
If we subtract 270 from 300, we get 30.
Since there are no more digits in the dividend, we add a zero to the remainder making it 300, and continue the process.

After the division, we end up with 683503.833 and a remainder of 0.003.