15155807 ÷ 280 
The aim is to understand the frequency of 280 in 15155807.

Step 1:
When dividing 1 by 280, we get 0 with a remainder of 1.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we take 0 away from 1, we end up with 1.
Include the next digit (5) from the dividend after 1, then repeat: 15 / 280

Advancing to step 2:
15 divided by 280 is 0 with a remainder of 15.
Use 0 as the next digit of our solution. 
Result so far: 0.0
Subtracting 0 from 15 leaves us with 15.
Fetch the next digit (1) from the dividend, attach it to 15 and continue: 151 / 280

Advancing to step 3:
280 can be fit into 151 0 times, resulting in a remainder of 151.
Put 0 as the next digit of the answer. 
Result so far: 0.0
If we subtract 0 from 151, we get 151.
Fetch the next digit (5) from the dividend, attach it to 151 and continue: 1515 / 280

Going ahead to step 4:
280 can be fit into 1515 5 times, resulting in a remainder of 115.
The number 5 becomes the next digit in our result. 
Result so far: 5.0
Deduct 1400 from 1515 and we're left with 115.
Fetch the next digit (5) from the dividend, attach it to 115 and continue: 1155 / 280

Advancing to step 5:
The number 280 fits into 1155 4 times, leaving a remainder of 35.
Write down 4 as next digit of the result. 
Result so far: 54.0
Subtract 1120 from 1155 to get 35.
Fetch the next digit (8) from the dividend, attach it to 35 and continue: 358 / 280

Going ahead to step 6:
280 can be fit into 358 1 times, resulting in a remainder of 78.
Use 1 as the next digit of our solution. 
Result so far: 541.0
If we take 280 away from 358, we end up with 78.
Bring next digit (0) of the dividend behind the 78 and repeat the process: 780 / 280

Advancing to step 7:
280 goes into 780 2 times with a remainder of 220.
Put 2 as the next digit of the answer. 
Result so far: 5412.0
If we subtract 560 from 780, we get 220.
Grab the next digit (7) from the dividend, add it to 220, then carry on: 2207 / 280

On to step 8:
280 goes into 2207 7 times with a remainder of 247.
Put 7 as the next digit of the answer. 
Result so far: 54127.0
Deduct 1960 from 2207 and we're left with 247.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2470, and continue the process.

Advancing to step 9:
The number 280 fits into 2470 8 times, leaving a remainder of 230.
Put 8 as the next digit of the answer. 
Result so far: 54127.8
Subtracting 2240 from 2470 leaves us with 230.
Since there are no more digits in the dividend, we add a zero to the remainder making it 2300, and continue the process.

Step 10:
280 goes into 2300 8 times with a remainder of 60.
The number 8 becomes the next digit in our result. 
Result so far: 54127.88
Subtracting 2240 from 2300 leaves us with 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

The final result is 54127.88 with a remainder of 0.06.