We divide 1233423 by 406
The aim is to understand the frequency of 406 in 1233423.

On to step 1:
1 divided by 406 is 0 with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 1, we get 1.
Grab the next digit (2) from the dividend, add it to 1, then carry on: 12 / 406

Going ahead to step 2:
12 divided by 406 is 0 with a remainder of 12.
Write down 0 as next digit of the result. 
Result so far: 0.0
Deduct 0 from 12 and we're left with 12.
Fetch the next digit (3) from the dividend, attach it to 12 and continue: 123 / 406

On to step 3:
406 goes into 123 0 times with a remainder of 123.
Record the quotient 0 as the next digit in the result. 
Result so far: 0.0
If we subtract 0 from 123, we get 123.
Grab the next digit (3) from the dividend, add it to 123, then carry on: 1233 / 406

Moving on to step 4:
1233 divided by 406 is 3 with a remainder of 15.
Put 3 as the next digit of the answer. 
Result so far: 3.0
If we take 1218 away from 1233, we end up with 15.
Grab the next digit (4) from the dividend, add it to 15, then carry on: 154 / 406

On to step 5:
If we divide 154 by 406, we get 0 and a remainder of 154.
The number 0 becomes the next digit in our result. 
Result so far: 30.0
Deduct 0 from 154 and we're left with 154.
Bring next digit (2) of the dividend behind the 154 and repeat the process: 1542 / 406

Going ahead to step 6:
406 goes into 1542 3 times with a remainder of 324.
Record the quotient 3 as the next digit in the result. 
Result so far: 303.0
If we subtract 1218 from 1542, we get 324.
Bring next digit (3) of the dividend behind the 324 and repeat the process: 3243 / 406

Moving on to step 7:
If we divide 3243 by 406, we get 7 and a remainder of 401.
The next digit of our result is 7. 
Result so far: 3037.0
Subtract 2842 from 3243 to get 401.
Since there are no more digits in the dividend, we add a zero to the remainder making it 4010, and continue the process.

Moving on to step 8:
If we divide 4010 by 406, we get 9 and a remainder of 356.
Record the quotient 9 as the next digit in the result. 
Result so far: 3037.9
If we subtract 3654 from 4010, we get 356.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3560, and continue the process.

Moving on to step 9:
If we divide 3560 by 406, we get 8 and a remainder of 312.
Put 8 as the next digit of the answer. 
Result so far: 3037.98
Deduct 3248 from 3560 and we're left with 312.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3120, and continue the process.

Advancing to step 10:
When dividing 3120 by 406, we get 7 with a remainder of 278.
Put 7 as the next digit of the answer. 
Result so far: 3037.987
If we take 2842 away from 3120, we end up with 278.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2780, and continue the process.

Step 11:
406 goes into 2780 6 times with a remainder of 344.
The number 6 becomes the next digit in our result. 
Result so far: 3037.9876
The remainder is 344 after subtracting 2436 from 2780.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3440, and continue the process.

Advancing to step 12:
If we divide 3440 by 406, we get 8 and a remainder of 192.
The number 8 becomes the next digit in our result. 
Result so far: 3037.98768
If we take 3248 away from 3440, we end up with 192.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1920, and continue the process.

On to step 13:
When dividing 1920 by 406, we get 4 with a remainder of 296.
Write down 4 as next digit of the result. 
Result so far: 3037.987684
The remainder is 296 after subtracting 1624 from 1920.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2960, and continue the process.

Moving on to step 14:
The number 406 fits into 2960 7 times, leaving a remainder of 118.
Put 7 as the next digit of the answer. 
Result so far: 3037.9876847
Subtracting 2842 from 2960 leaves us with 118.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1180, and continue the process.

Step 15:
The number 406 fits into 1180 2 times, leaving a remainder of 368.
Write down 2 as next digit of the result. 
Result so far: 3037.98768472
If we subtract 812 from 1180, we get 368.
Since there are no more digits in the dividend, we add a zero to the remainder making it 3680, and continue the process.

After the division, we end up with 3037.98768472 and a remainder of 3.68e-07.