Let's divide 21215124 by 860
We want to figure out the number of times 21215124 can be divided by 860.

On to step 1:
860 can be fit into 2 0 times, resulting in a remainder of 2.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 2 and we're left with 2.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 860

On to step 2:
860 can be fit into 21 0 times, resulting in a remainder of 21.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 21 and we're left with 21.
Fetch the next digit (2) from the dividend, attach it to 21 and continue: 212 / 860

Going ahead to step 3:
860 can be fit into 212 0 times, resulting in a remainder of 212.
Write down 0 as next digit of the result. 
Result so far: 0.0
Subtract 0 from 212 to get 212.
Include the next digit (1) from the dividend after 212, then repeat: 2121 / 860

Moving on to step 4:
860 can be fit into 2121 2 times, resulting in a remainder of 401.
The number 2 becomes the next digit in our result. 
Result so far: 2.0
Subtracting 1720 from 2121 leaves us with 401.
Bring next digit (5) of the dividend behind the 401 and repeat the process: 4015 / 860

On to step 5:
4015 divided by 860 is 4 with a remainder of 575.
Record the quotient 4 as the next digit in the result. 
Result so far: 24.0
If we take 3440 away from 4015, we end up with 575.
Grab the next digit (1) from the dividend, add it to 575, then carry on: 5751 / 860

On to step 6:
5751 divided by 860 is 6 with a remainder of 591.
Use 6 as the next digit of our solution. 
Result so far: 246.0
Subtract 5160 from 5751 to get 591.
Fetch the next digit (2) from the dividend, attach it to 591 and continue: 5912 / 860

Step 7:
860 can be fit into 5912 6 times, resulting in a remainder of 752.
Record the quotient 6 as the next digit in the result. 
Result so far: 2466.0
The remainder is 752 after subtracting 5160 from 5912.
Take the next digit (4) from the dividend and append it to 752, then repeat: 7524 / 860

Moving on to step 8:
If we divide 7524 by 860, we get 8 and a remainder of 644.
Record the quotient 8 as the next digit in the result. 
Result so far: 24668.0
Subtracting 6880 from 7524 leaves us with 644.
Since there are no more digits in the dividend, we add a zero to the remainder making it 6440, and continue the process.

On to step 9:
860 goes into 6440 7 times with a remainder of 420.
Put 7 as the next digit of the answer. 
Result so far: 24668.7
The remainder is 420 after subtracting 6020 from 6440.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4200, and continue the process.

Let's proceed to step 10:
860 can be fit into 4200 4 times, resulting in a remainder of 760.
The next digit of our result is 4. 
Result so far: 24668.74
Deduct 3440 from 4200 and we're left with 760.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7600, and continue the process.

Let's proceed to step 11:
The number 860 fits into 7600 8 times, leaving a remainder of 720.
The next digit of our result is 8. 
Result so far: 24668.748
Subtract 6880 from 7600 to get 720.
Since there are no more digits in the dividend, we add a zero to the remainder making it 7200, and continue the process.

Moving on to step 12:
7200 divided by 860 is 8 with a remainder of 320.
The number 8 becomes the next digit in our result. 
Result so far: 24668.7488
If we take 6880 away from 7200, we end up with 320.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3200, and continue the process.

The quotient of the division is 24668.7488, and the remainder is 0.0032.