421577 divided by 40 
The aim is to understand the frequency of 40 in 421577.

On to step 1:
40 can be fit into 4 0 times, resulting in a remainder of 4.
The next digit of our result is 0. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Append the next digit (2) from the dividend to 4 and continue with: 42 / 40

On to step 2:
When dividing 42 by 40, we get 1 with a remainder of 2.
Write down 1 as next digit of the result. 
Result so far: 1.0
If we subtract 40 from 42, we get 2.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 40

Going ahead to step 3:
The number 40 fits into 21 0 times, leaving a remainder of 21.
The number 0 becomes the next digit in our result. 
Result so far: 10.0
Deduct 0 from 21 and we're left with 21.
Fetch the next digit (5) from the dividend, attach it to 21 and continue: 215 / 40

Step 4:
40 goes into 215 5 times with a remainder of 15.
Put 5 as the next digit of the answer. 
Result so far: 105.0
If we take 200 away from 215, we end up with 15.
Take the next digit (7) from the dividend and append it to 15, then repeat: 157 / 40

Step 5:
157 divided by 40 is 3 with a remainder of 37.
Record the quotient 3 as the next digit in the result. 
Result so far: 1053.0
If we subtract 120 from 157, we get 37.
Take the next digit (7) from the dividend and append it to 37, then repeat: 377 / 40

On to step 6:
When dividing 377 by 40, we get 9 with a remainder of 17.
Write down 9 as next digit of the result. 
Result so far: 10539.0
If we subtract 360 from 377, we get 17.
Since there are no more digits in the dividend, we add a zero to the remainder making it 170, and continue the process.

Moving on to step 7:
When dividing 170 by 40, we get 4 with a remainder of 10.
The number 4 becomes the next digit in our result. 
Result so far: 10539.4
Subtract 160 from 170 to 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.

Advancing to step 8:
40 goes into 100 2 times with a remainder of 20.
The number 2 becomes the next digit in our result. 
Result so far: 10539.42
If we subtract 80 from 100, we get 20.
Since there are no more digits in the dividend, we add a zero to the remainder making it 200, and continue the process.

Going ahead to step 9:
40 goes into 200 5 times with a remainder of 0.
Record the quotient 5 as the next digit in the result. 
Result so far: 10539.425
The remainder is 0 after subtracting 200 from 200.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Going ahead to step 10:
When dividing 0 by 40, we get 0 with a remainder of 0.
The next digit of our result is 0. 
Result so far: 10539.425
If we subtract 0 from 0, we get 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Step 11:
If we divide 0 by 40, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 10539.425
The remainder is 0 after subtracting 0 from 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

The final outcome is 10539.425, with a leftover of 0.0.