#!/bin/bash
#
TOT=33
RES=$(echo "if ($TOT % 10) (($TOT / 10)+1)  * 10 else ($TOT /10 ) * 10
" | bc)
echo "Tried $TOT result was $RES"
TOT=102
RES=$(echo "if ($TOT % 10) (($TOT / 10)+1)  * 10 else ($TOT /10 ) * 10
" | bc)
echo "Tried $TOT result was $RES"
RES=$(echo "if ($TOT % 10) (($TOT / 10)+1)  * 10 else ($TOT /10 ) * 10
" | bc)
TOT=70
RES=$(echo "if ($TOT % 10) (($TOT / 10)+1)  * 10 else ($TOT /10 ) * 10
" | bc)
echo "Tried $TOT result was $RES"

 if totals bigger than 10 (e.g 18)
 take off the second digit to leave the first digit (the 1)
 add 1 to that number = 2
 stick a zero on the end of that = 20
 calculate total (18) - the number weve just got(20).
 
 if the totals smaller than 10 (e.g 8)
 do 10 - the total (10 - 8)

sergei@amdam2:~/junk> cat -n gen_and_add_random_number.pl
     1  #!/usr/bin/perl -w
     2
     3  use strict;
     4
     5  my $number_of_random_numbers = 15;
     6  my $max_random_number = 10;
     7
     8  my @random_numbers = map{int(rand($max_random_number + 1))} (1 .. $number_of_random_numbers); # this is random numbers generation
     9
    10  my $sum_of_random_numbers = 0;
    11  map {$sum_of_random_numbers += $_;} @random_numbers; # actual summation
    12
    13  warn "\@random_numbers=@random_numbers";
    14  warn "\$sum_of_random_numbers=$sum_of_random_numbers";
    15
sergei@amdam2:~/junk> ./gen_and_add_random_number.pl
@random_numbers=2 2 1 1 9 6 2 8 5 3 0 2 7 1 0 at ./gen_and_add_random_number.pl line 13.
$sum_of_random_numbers=49 at ./gen_and_add_random_number.pl line 14.

Take only the first digit (e.g. 18 mod 10 = 8)
if it's not 0 then
  (10 - digit) is the number you want (10 - 8 = 2)
else
  You don't need another number

if [ "$total" -lt "10" ];
 then let "chkbit = 10"
elif [ "$total" == "10" || "$total" == "20" || $total" == "30" || "$total" == "40" || "$total" == "50" || $total" == "60" || "$total" == "70" ];
 then let "chkbit = 0"
else
 #this is jut in for testing purposes.
 let "chkbit = 500"
fi

import random
numrand = 15
maxrand = 10
rand = [ random.randint(1,maxrand) for i in range(1,numrand)]
summation = sum(rand)
print "random numbers: ", rand
print "sum of them: ",summation

# ./test.py
random numbers:  [7, 2, 9, 6, 3, 2, 4, 10, 1, 8, 9, 8, 1, 1]
sum of them:  71
#

#code below was nicked and heavily modified from a dice random number generator
#
PIPS=10         #generate numbers from 0 - 9
MAXTHROWS=13 #This is the number of single digit numbers
throw=0         # Throw count.

#generate 13 one digit numbers...
number2=`while [ "$throw" -lt "$MAXTHROWS" ]
do
  let "die1 = RANDOM % $PIPS"
  echo $die1
  let "throw += 1"
done`
#
#thats all the stolen code...

#select only the even digits (2, 4, 6 etc)
array2=($number2)
for (( i = 0 ; i < ${#array2[@]} ; i++ ))
do
  let "i += 1"
  addevens=`echo ${array2[$i]}`
  ADDEVE=( "${ADDEVE[@]}" "$addevens" )
done

array=($number2)
for (( i = -1 ; i < ${#array[@]} ; i++ ))
do
  do let "i += 1"
  #echo out the other digits, if the numbers are greater than 10 double them and then subtract 9
  NUMB=`echo ${array[$i]}`
  let MULT=`expr $NUMB*2`
    if [ "$MULT" -gt "9" ];
      then let "MULT -= 9"
    fi
  #write numbers into an array
  addodds=`echo $MULT`
  ADDAR=( "${ADDAR[@]}" "$addodds" )
done

let totaleve=`expr ${ADDEVE[0]}+${ADDEVE[1]}+${ADDEVE[2]}+${ADDEVE[3]}+${ADDEVE[4]}+${ADDEVE[5]}`

#add all the numbers contained in the array together
let totalodd=`expr ${ADDAR[0]}+${ADDAR[1]}+${ADDAR[2]}+${ADDAR[3]}+${ADDAR[4]}+${ADDAR[5]}+${ADDAR[6]}`
let total=`expr $totalodd+$totaleve`

#the following was just for testing purposes, it was done in the early stages so arrays may be invalid now.
#
#echo the odd total is $totalodd
#echo the even total is $totaleve
#echo the grand total is $total
#echo "list of odd (doubled) elements : ${ADDAR[@]}"
#echo "list of even array elements    : ${ADDEVE[@]}"
#echo "total of all elements in the array: $total"

#if the total is 10 the checkbit will be zero as the totals already divisible by 10

if [ "$total" -lt "10" ];then
  let "chkbit = 10"
  let LAST=`expr $chkbit - $total`

#if the totals already a possible multiple of 10 the checkbit will be zero
elif [[ "$total" -eq "10" || "$total" -eq "20" || "$total" -eq "30" || "$total" -eq "40" || "$total" -eq "50"  || "$total" -eq "60"  || "$total" -eq "70"|| "$
total" -eq "80" || "$total" -eq "90" || "$total" -eq "100" || "$total" -eq "110"  || "$total" -eq "120"  || "$total" -eq "130"  ]]; then
  let "chkbit = 0"
  let LAST=$chkbit
#if the total is a number not divisible by 10 take the first digit of the total, add one to it and then multiply it by 10 and assign it a variable called chkbit, subtract the total from the checkbit to give a grand total divisible by 10.
else
  totalup=`echo $total | cut -c1`
  let chkbit=`expr $totalup+1`
  let chkbit=`expr $chkbit*10`
  let LAST=`expr $chkbit - $total`
fi
echo -n $number2 $LAST
echo

exit 0