We look at the division of 213138 by 72 
The aim is to understand the frequency of 72 in 213138.

Let's proceed to step 1:
72 can be fit into 2 0 times, resulting in a remainder of 2.
Use 0 as the next digit of our solution. 
Result so far: 0.0
If we subtract 0 from 2, we get 2.
Fetch the next digit (1) from the dividend, attach it to 2 and continue: 21 / 72

Going ahead to step 2:
The number 72 fits into 21 0 times, leaving a remainder of 21.
The next digit of our result is 0. 
Result so far: 0.0
Deduct 0 from 21 and we're left with 21.
Take the next digit (3) from the dividend and append it to 21, then repeat: 213 / 72

Step 3:
213 divided by 72 is 2 with a remainder of 69.
Write down 2 as next digit of the result. 
Result so far: 2.0
Subtract 144 from 213 to get 69.
Fetch the next digit (1) from the dividend, attach it to 69 and continue: 691 / 72

Going ahead to step 4:
The number 72 fits into 691 9 times, leaving a remainder of 43.
Write down 9 as next digit of the result. 
Result so far: 29.0
If we take 648 away from 691, we end up with 43.
Append the next digit (3) from the dividend to 43 and continue with: 433 / 72

Going ahead to step 5:
72 can be fit into 433 6 times, resulting in a remainder of 1.
Use 6 as the next digit of our solution. 
Result so far: 296.0
If we take 432 away from 433, we end up with 1.
Grab the next digit (8) from the dividend, add it to 1, then carry on: 18 / 72

Let's proceed to step 6:
72 goes into 18 0 times with a remainder of 18.
The number 0 becomes the next digit in our result. 
Result so far: 2960.0
The remainder is 18 after subtracting 0 from 18.
Since there are no more digits in the dividend, we add a zero to the remainder making it 180, and continue the process.

Going ahead to step 7:
If we divide 180 by 72, we get 2 and a remainder of 36.
Put 2 as the next digit of the answer. 
Result so far: 2960.2
If we take 144 away from 180, we end up with 36.
Since there are no more digits in the dividend, we add a zero to the remainder making it 360, and continue the process.

Step 8:
The number 72 fits into 360 5 times, leaving a remainder of 0.
Write down 5 as next digit of the result. 
Result so far: 2960.25
If we subtract 360 from 360, 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.

Advancing to step 9:
If we divide 0 by 72, we get 0 and a remainder of 0.
Use 0 as the next digit of our solution. 
Result so far: 2960.25
Deduct 0 from 0 and we're left with 0.
Since there are no more digits in the dividend, we add a zero to the remainder making it 0, and continue the process.

Moving on to step 10:
72 can be fit into 0 0 times, resulting in a remainder of 0.
Record the quotient 0 as the next digit in the result. 
Result so far: 2960.25
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.

The final outcome is 2960.25, with a leftover of 0.0.