We divide 151781 by 21
We want to figure out the number of times 151781 can be divided by 21.

Step 1:
21 goes into 1 0 times with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Subtract 0 from 1 to get 1.
Bring next digit (5) of the dividend behind the 1 and repeat the process: 15 / 21

Going ahead to step 2:
21 goes into 15 0 times with a remainder of 15.
The next digit of our result is 0. 
Result so far: 0.0
Subtracting 0 from 15 leaves us with 15.
Take the next digit (1) from the dividend and append it to 15, then repeat: 151 / 21

Moving on to step 3:
21 can be fit into 151 7 times, resulting in a remainder of 4.
The number 7 becomes the next digit in our result. 
Result so far: 7.0
If we subtract 147 from 151, we get 4.
Bring next digit (7) of the dividend behind the 4 and repeat the process: 47 / 21

Step 4:
21 goes into 47 2 times with a remainder of 5.
Write down 2 as next digit of the result. 
Result so far: 72.0
If we subtract 42 from 47, we get 5.
Append the next digit (8) from the dividend to 5 and continue with: 58 / 21

On to step 5:
If we divide 58 by 21, we get 2 and a remainder of 16.
Use 2 as the next digit of our solution. 
Result so far: 722.0
The remainder is 16 after subtracting 42 from 58.
Bring next digit (1) of the dividend behind the 16 and repeat the process: 161 / 21

Going ahead to step 6:
161 divided by 21 is 7 with a remainder of 14.
Use 7 as the next digit of our solution. 
Result so far: 7227.0
Subtracting 147 from 161 leaves us with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

On to step 7:
If we divide 140 by 21, we get 6 and a remainder of 14.
Write down 6 as next digit of the result. 
Result so far: 7227.6
The remainder is 14 after subtracting 126 from 140.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

Moving on to step 8:
When dividing 140 by 21, we get 6 with a remainder of 14.
Write down 6 as next digit of the result. 
Result so far: 7227.66
If we take 126 away from 140, we end up with 14.
Since there are no more digits in the dividend, we add a zero to the remainder making it 140, and continue the process.

After the division, we end up with 7227.66 and a remainder of 0.014.