We look at the division of 75964 by 21 
Let's see how many times 21 fits into 75964.

Moving on to step 1:
21 can be fit into 7 0 times, resulting in a remainder of 7.
Use 0 as the next digit of our solution. 
Result so far: 0.0
The remainder is 7 after subtracting 0 from 7.
Take the next digit (5) from the dividend and append it to 7, then repeat: 75 / 21

On to step 2:
If we divide 75 by 21, we get 3 and a remainder of 12.
The number 3 becomes the next digit in our result. 
Result so far: 3.0
Deduct 63 from 75 and we're left with 12.
Append the next digit (9) from the dividend to 12 and continue with: 129 / 21

Going ahead to step 3:
When dividing 129 by 21, we get 6 with a remainder of 3.
The next digit of our result is 6. 
Result so far: 36.0
If we subtract 126 from 129, we get 3.
Append the next digit (6) from the dividend to 3 and continue with: 36 / 21

On to step 4:
The number 21 fits into 36 1 times, leaving a remainder of 15.
Record the quotient 1 as the next digit in the result. 
Result so far: 361.0
If we subtract 21 from 36, we get 15.
Include the next digit (4) from the dividend after 15, then repeat: 154 / 21

Step 5:
21 goes into 154 7 times with a remainder of 7.
The number 7 becomes the next digit in our result. 
Result so far: 3617.0
If we subtract 147 from 154, we get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Going ahead to step 6:
If we divide 70 by 21, we get 3 and a remainder of 7.
The number 3 becomes the next digit in our result. 
Result so far: 3617.3
Subtract 63 from 70 to get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

Moving on to step 7:
21 goes into 70 3 times with a remainder of 7.
Write down 3 as next digit of the result. 
Result so far: 3617.33
If we subtract 63 from 70, we get 7.
Since there are no more digits in the dividend, we add a zero to the remainder making it 70, and continue the process.

The quotient of the division is 3617.33, and the remainder is 0.007.