121651 ÷ 21 
We're looking to find how many times 21 goes into 121651.

On to step 1:
When dividing 1 by 21, we get 0 with a remainder of 1.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Append the next digit (2) from the dividend to 1 and continue with: 12 / 21

On to step 2:
12 divided by 21 is 0 with a remainder of 12.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
Subtract 0 from 12 to get 12.
Take the next digit (1) from the dividend and append it to 12, then repeat: 121 / 21

Going ahead to step 3:
21 goes into 121 5 times with a remainder of 16.
Write down 5 as next digit of the result. 
Result so far: 5.0
The remainder is 16 after subtracting 105 from 121.
Include the next digit (6) from the dividend after 16, then repeat: 166 / 21

Step 4:
21 goes into 166 7 times with a remainder of 19.
The number 7 becomes the next digit in our result. 
Result so far: 57.0
Deduct 147 from 166 and we're left with 19.
Bring next digit (5) of the dividend behind the 19 and repeat the process: 195 / 21

Going ahead to step 5:
The number 21 fits into 195 9 times, leaving a remainder of 6.
The next digit of our result is 9. 
Result so far: 579.0
If we take 189 away from 195, we end up with 6.
Include the next digit (1) from the dividend after 6, then repeat: 61 / 21

Going ahead to step 6:
61 divided by 21 is 2 with a remainder of 19.
Put 2 as the next digit of the answer. 
Result so far: 5792.0
Subtracting 42 from 61 leaves us with 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Going ahead to step 7:
The number 21 fits into 190 9 times, leaving a remainder of 1.
The next digit of our result is 9. 
Result so far: 5792.9
If we take 189 away from 190, we end up with 1.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Going ahead to step 8:
If we divide 10 by 21, we get 0 and a remainder of 10.
The number 0 becomes the next digit in our result. 
Result so far: 5792.9
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

Going ahead to step 9:
The number 21 fits into 100 4 times, leaving a remainder of 16.
Use 4 as the next digit of our solution. 
Result so far: 5792.904
If we subtract 84 from 100, we get 16.
Since there are no more digits in the dividend, we add a zero to the remainder making it 160, and continue the process.

On to step 10:
21 can be fit into 160 7 times, resulting in a remainder of 13.
The number 7 becomes the next digit in our result. 
Result so far: 5792.9047
Subtracting 147 from 160 leaves us with 13.
Since there are no more digits in the dividend, we add a zero to the remainder making it 130, and continue the process.

Step 11:
130 divided by 21 is 6 with a remainder of 4.
The next digit of our result is 6. 
Result so far: 5792.90476
Deduct 126 from 130 and we're left with 4.
Since there are no more digits in the dividend, we add a zero to the remainder making it 40, and continue the process.

On to step 12:
21 can be fit into 40 1 times, resulting in a remainder of 19.
Use 1 as the next digit of our solution. 
Result so far: 5792.904761
Subtract 21 from 40 to get 19.
Since there are no more digits in the dividend, we add a zero to the remainder making it 190, and continue the process.

Moving on to step 13:
21 can be fit into 190 9 times, resulting in a remainder of 1.
The number 9 becomes the next digit in our result. 
Result so far: 5792.9047619
The remainder is 1 after subtracting 189 from 190.
Since there are no more digits in the dividend, we add a zero to the remainder making it 10, and continue the process.

Advancing to step 14:
21 can be fit into 10 0 times, resulting in a remainder of 10.
Use 0 as the next digit of our solution. 
Result so far: 5792.9047619
If we subtract 0 from 10, we get 10.
Since there are no more digits in the dividend, we add a zero to the remainder making it 100, and continue the process.

The quotient of the division is 5792.9047619, and the remainder is 1e-08.