337188 ÷ 21 
Our goal is to divide 337188 by 21.

Step 1:
If we divide 3 by 21, we get 0 and a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 3 to get 3.
Take the next digit (3) from the dividend and append it to 3, then repeat: 33 / 21

On to step 2:
When dividing 33 by 21, we get 1 with a remainder of 12.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 21 from 33, we get 12.
Take the next digit (7) from the dividend and append it to 12, then repeat: 127 / 21

Step 3:
21 goes into 127 6 times with a remainder of 1.
Write down 6 as next digit of the result. 
Result so far: 16.0
The remainder is 1 after subtracting 126 from 127.
Append the next digit (1) from the dividend to 1 and continue with: 11 / 21

Going ahead to step 4:
The number 21 fits into 11 0 times, leaving a remainder of 11.
Write down 0 as next digit of the result. 
Result so far: 160.0
If we take 0 away from 11, we end up with 11.
Fetch the next digit (8) from the dividend, attach it to 11 and continue: 118 / 21

Step 5:
The number 21 fits into 118 5 times, leaving a remainder of 13.
Record the quotient 5 as the next digit in the result. 
Result so far: 1605.0
If we subtract 105 from 118, we get 13.
Grab the next digit (8) from the dividend, add it to 13, then carry on: 138 / 21

Step 6:
The number 21 fits into 138 6 times, leaving a remainder of 12.
Write down 6 as next digit of the result. 
Result so far: 16056.0
Deduct 126 from 138 and we're left with 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Step 7:
When dividing 120 by 21, we get 5 with a remainder of 15.
Write down 5 as next digit of the result. 
Result so far: 16056.5
Subtracting 105 from 120 leaves us with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 8:
When dividing 150 by 21, we get 7 with a remainder of 3.
Record the quotient 7 as the next digit in the result. 
Result so far: 16056.57
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

Advancing to step 9:
If we divide 30 by 21, we get 1 and a remainder of 9.
The number 1 becomes the next digit in our result. 
Result so far: 16056.571
Deduct 21 from 30 and we're left with 9.
Since there are no more digits in the dividend, we add a zero to the remainder making it 90, and continue the process.

Advancing to step 10:
21 can be fit into 90 4 times, resulting in a remainder of 6.
Record the quotient 4 as the next digit in the result. 
Result so far: 16056.5714
If we take 84 away from 90, we end up with 6.
Since there are no more digits in the dividend, we add a zero to the remainder making it 60, and continue the process.

Advancing to step 11:
The number 21 fits into 60 2 times, leaving a remainder of 18.
Write down 2 as next digit of the result. 
Result so far: 16056.57142
Subtracting 42 from 60 leaves us with 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Moving on to step 12:
21 can be fit into 180 8 times, resulting in a remainder of 12.
Use 8 as the next digit of our solution. 
Result so far: 16056.571428
Subtract 168 from 180 to get 12.
Since there are no more digits in the dividend, we add a zero to the remainder making it 120, and continue the process.

Advancing to step 13:
When dividing 120 by 21, we get 5 with a remainder of 15.
Use 5 as the next digit of our solution. 
Result so far: 16056.5714285
Deduct 105 from 120 and we're left with 15.
Since there are no more digits in the dividend, we add a zero to the remainder making it 150, and continue the process.

Let's proceed to step 14:
The number 21 fits into 150 7 times, leaving a remainder of 3.
Write down 7 as next digit of the result. 
Result so far: 16056.57142857
Deduct 147 from 150 and we're left with 3.
Since there are no more digits in the dividend, we add a zero to the remainder making it 30, and continue the process.

The quotient of the division is 16056.57142857, and the remainder is 3e-09.