42209086 ÷ 306 
The aim is to understand the frequency of 306 in 42209086.

Step 1:
When dividing 4 by 306, we get 0 with a remainder of 4.
Write down 0 as next digit of the result. 
Result so far: 0.0
If we subtract 0 from 4, we get 4.
Bring next digit (2) of the dividend behind the 4 and repeat the process: 42 / 306

Step 2:
The number 306 fits into 42 0 times, leaving a remainder of 42.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
Subtracting 0 from 42 leaves us with 42.
Fetch the next digit (2) from the dividend, attach it to 42 and continue: 422 / 306

Step 3:
306 goes into 422 1 times with a remainder of 116.
Use 1 as the next digit of our solution. 
Result so far: 1.0
If we subtract 306 from 422, we get 116.
Append the next digit (0) from the dividend to 116 and continue with: 1160 / 306

Step 4:
If we divide 1160 by 306, we get 3 and a remainder of 242.
Write down 3 as next digit of the result. 
Result so far: 13.0
If we subtract 918 from 1160, we get 242.
Bring next digit (9) of the dividend behind the 242 and repeat the process: 2429 / 306

Going ahead to step 5:
When dividing 2429 by 306, we get 7 with a remainder of 287.
Write down 7 as next digit of the result. 
Result so far: 137.0
Subtract 2142 from 2429 to get 287.
Fetch the next digit (0) from the dividend, attach it to 287 and continue: 2870 / 306

Advancing to step 6:
2870 divided by 306 is 9 with a remainder of 116.
The number 9 becomes the next digit in our result. 
Result so far: 1379.0
If we take 2754 away from 2870, we end up with 116.
Take the next digit (8) from the dividend and append it to 116, then repeat: 1168 / 306

Advancing to step 7:
The number 306 fits into 1168 3 times, leaving a remainder of 250.
The number 3 becomes the next digit in our result. 
Result so far: 13793.0
The remainder is 250 after subtracting 918 from 1168.
Take the next digit (6) from the dividend and append it to 250, then repeat: 2506 / 306

Step 8:
When dividing 2506 by 306, we get 8 with a remainder of 58.
Put 8 as the next digit of the answer. 
Result so far: 137938.0
The remainder is 58 after subtracting 2448 from 2506.
Since there are no more digits in the dividend, we add a zero to the remainder making it 580, and continue the process.

Going ahead to step 9:
When dividing 580 by 306, we get 1 with a remainder of 274.
Record the quotient 1 as the next digit in the result. 
Result so far: 137938.1
If we subtract 306 from 580, we get 274.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2740, and continue the process.

On to step 10:
2740 divided by 306 is 8 with a remainder of 292.
Use 8 as the next digit of our solution. 
Result so far: 137938.18
Subtract 2448 from 2740 to get 292.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2920, and continue the process.

Let's proceed to step 11:
306 goes into 2920 9 times with a remainder of 166.
Write down 9 as next digit of the result. 
Result so far: 137938.189
Subtracting 2754 from 2920 leaves us with 166.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1660, and continue the process.

Moving on to step 12:
The number 306 fits into 1660 5 times, leaving a remainder of 130.
The next digit of our result is 5. 
Result so far: 137938.1895
Subtracting 1530 from 1660 leaves us with 130.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1300, and continue the process.

Advancing to step 13:
306 can be fit into 1300 4 times, resulting in a remainder of 76.
Record the quotient 4 as the next digit in the result. 
Result so far: 137938.18954
If we take 1224 away from 1300, we end up with 76.
Since there are no more digits in the dividend, we add a zero to the remainder making it 760, and continue the process.

Step 14:
306 can be fit into 760 2 times, resulting in a remainder of 148.
Record the quotient 2 as the next digit in the result. 
Result so far: 137938.189542
If we subtract 612 from 760, we get 148.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1480, and continue the process.

Moving on to step 15:
1480 divided by 306 is 4 with a remainder of 256.
The next digit of our result is 4. 
Result so far: 137938.1895424
Subtracting 1224 from 1480 leaves us with 256.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2560, and continue the process.

Advancing to step 16:
2560 divided by 306 is 8 with a remainder of 112.
The number 8 becomes the next digit in our result. 
Result so far: 137938.18954248
The remainder is 112 after subtracting 2448 from 2560.
Since there are no more digits in the dividend, we add a zero to the remainder making it 1120, and continue the process.

The final result is 137938.18954248 with a remainder of 1.12e-07.