Step 1:
Find some books on basic mathematics/Number theory.
* Elementary Number Theory with Applications
-Thomas Koshy
*Concrete mathematics
-Donald Knuth

Step 2:
Select an programming language to implement those mathematics you have learnt. Now-a-days, C,C++,JAVA are the most popular and widely used languages. If you are newbie ,I will suggest you to learn C because it is the most efficient and easiest language. Most of important softwares and Some of operating systems are developed in C.
If you are not a student of CSE background,don’t be afraid,because you can learn it easily. You can learn this from this book. Ya, all the newbies who are related to CSE,this book is also for you too.
*Art Of Programming contest
* Programming with C
-Bayron Gottfried
Step 3:
Now you have learnt a little bit of mathematics, at least one of the programming languages, it’s time go now. What to do? You have to solve problems.There are many Online judges,In which there are thousands of problem descriptions with the facility to judge your solution ,is it ok or not,I will mention “Is the solution efficient or not”.
As you are newbie I will suggest you to use UVA at first . For this you have to open an account on this site.you can browse problems of their site. The first job of you to read the problem carefully,find the solution ,then code it.
What is coding? If you have learnt any of the programming languages, don’t ask it again.You have to write a code which will take input and provide with outputs as the problem description. After login you have to submit your solution to the onlinejudge.That machine will judge your solution in RE (runtime error),TE (time limit exceede),WA (wrong answer),PA (presentation error) and AC (accepted).
When submitting,you have take some measures which will be described below.
You can track your progress from here .
After solving some of problems,you should not be limited only in a single judges.

Here are some others OJs.
*SPOJ
*Light OJ
*Topcoder
*Codeforces

Here are some of websites/blogs which can be useful for you too.
*Smilitude
* UVA FORUM

Problems solving with C:
A sample code for submitting a problem is given below.
[code]
#include<stdio.h>
int main()
{
int testcase,input,I,j,k;
while(scanf(“%d”,&input)==1)
{
//your solution exists here
If(input ==2)
printf(“two”);
else
printf(“Not two”);
}
return 0;
}
[/code]

Now practice problem solving. You must attend free online contests to judge yourself.

For any kind of help or suggestions
I am here