# [racket-users] Long division algorithm in HtDP way

```Dear Racketeers!

I would like to write the function divide in racket, for performing the long
division, which would print the whole computational process, as the elementary
school pupils do. For example, the call (divide 5432, 12) should print this:```
```
5432 : 12 = 452
-48
--
63
-60
--
32
-24
--
8
=

Finally, I wrote this function in python, but I'm not happy about it because
I've been "tinkering around" and I feel that it can be much better written by
following the principles described in HtDP. The problem is I don't know how to
do that, though I read the book and solved a lot of problems from it. I simply
don't know how to "derive" clean and nice program for this function.

My (ugly) python code looks like this:

def divide(x, y):
if x < y:
return 0, x
x = str(x)
q = ""
r = ""
workings = ""
firsttime = True
for i in range(1, len(x) + 1):
r = r + "0"
num = int(r) + int(x[i-1])
sum = 0
m = 0
while sum + y <= num:
m += 1
sum += y
r = str(num - sum)
q = q + str(m)
ls = len(str(sum))
if sum == 0 and firsttime:
continue
firsttime = False
workings += (i-ls)* " " + "-" + str(sum) + "\n"
workings += (i + 1 -ls) * " " + ls * "-" + "\n"
workings += (i + 1 - len(r)) * " " + r + ("" if i >= len(x) else x[i])
+ "\n"

workings += (len(x) - len(r) + 1) * " " + len(r) * "=" + "\n"
print(" " + x + " : " + str(y) + " = " + str(int(q)) + "\n" + workings)

I'm wondering how to write nice and clean version of the above program in the
proper HtDP way. Can someone here show how to solve this problem strictly
following the HtDP methodology?

Nice regards,
Jaroslaw Modry

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