We look at the division of 351257 by 77 
The aim is to understand the frequency of 77 in 351257.

Step 1:
When dividing 3 by 77, we get 0 with a remainder of 3.
Put 0 as the next digit of the answer. 
Result so far: 0.0
Deduct 0 from 3 and we're left with 3.
Fetch the next digit (5) from the dividend, attach it to 3 and continue: 35 / 77

Going ahead to step 2:
If we divide 35 by 77, we get 0 and a remainder of 35.
The number 0 becomes the next digit in our result. 
Result so far: 0.0
If we subtract 0 from 35, we get 35.
Append the next digit (1) from the dividend to 35 and continue with: 351 / 77

Let's proceed to step 3:
If we divide 351 by 77, we get 4 and a remainder of 43.
Put 4 as the next digit of the answer. 
Result so far: 4.0
If we subtract 308 from 351, we get 43.
Grab the next digit (2) from the dividend, add it to 43, then carry on: 432 / 77

Step 4:
77 can be fit into 432 5 times, resulting in a remainder of 47.
Put 5 as the next digit of the answer. 
Result so far: 45.0
Subtracting 385 from 432 leaves us with 47.
Grab the next digit (5) from the dividend, add it to 47, then carry on: 475 / 77

Going ahead to step 5:
The number 77 fits into 475 6 times, leaving a remainder of 13.
Write down 6 as next digit of the result. 
Result so far: 456.0
If we subtract 462 from 475, we get 13.
Append the next digit (7) from the dividend to 13 and continue with: 137 / 77

Moving on to step 6:
137 divided by 77 is 1 with a remainder of 60.
Write down 1 as next digit of the result. 
Result so far: 4561.0
Subtract 77 from 137 to get 60.
Since there are no more digits in the dividend, we add a zero to the remainder making it 600, and continue the process.

Step 7:
If we divide 600 by 77, we get 7 and a remainder of 61.
The next digit of our result is 7. 
Result so far: 4561.7
Subtracting 539 from 600 leaves us with 61.
Since there are no more digits in the dividend, we add a zero to the remainder making it 610, and continue the process.

Step 8:
The number 77 fits into 610 7 times, leaving a remainder of 71.
Write down 7 as next digit of the result. 
Result so far: 4561.77
Subtract 539 from 610 to get 71.
Since there are no more digits in the dividend, we add a zero to the remainder making it 710, and continue the process.

After the division, we end up with 4561.77 and a remainder of 0.071.