Understanding the Math Behind Fraction Multiplication | Maths Explanation for C# Kids
Learning how to multiply fractions in C# is a great way to combine math skills with coding. This tutorial is designed for junior secondary students who want to understand fraction multiplication using simple C# classes and constructors.
Multiplying fractions is pretty straightforward:
Cancel out all common factors between numerators and denominators,
then multiply whatever is left numerator to numerator and
denominator to denominator.
In this lesson, we'll walk through the step-by-step method of multiplying fractions using C#. You'll learn how to define a class, use constructors, and apply logic to find mutual factors and simplify results.
Step-by-Step Explanation of Algorithm to Multiply Fractions in C#
This C# algorithm for fractions shows how to multiply two fractions and reduce them to their lowest terms.
It's a great math coding project for beginners.
Understanding how to multiply multiple fractions in C# helps students build both computational thinking and math fluency.
It's a foundational skill for more advanced topics like algebra and data science.
If we have
4/9 x 21/8;
Step 1:
Find any common factor between any numerator and any denominator.
Step 2:
Cancel out any such common factor.
| = | X | 7 | |
| 4 | 21 | ||
| 9 | 8 | ||
| 3 |
Step 3:
Repeat Steps 1 & 2 recursively until there are no more common factors.
| = | 1 | X | |
| 4 | 7 | ||
| 3 | 8 | ||
| 2 |
| = | 7 |
| 6 |
Create a new C# class file;
call it MultiplyFraction.
Type out the adjoining C# code for multiplying fractions.
Note: You can comment out the LowestTerm C# object code in the main class from the previous lesson or simply continue from where it stopped.
So! C# Fun Practice Exercise - Multiply Fractions
As a fun practice exercise, feel free to try out your own fractions with different numerators and denominators, and see how the C# code multiplies those fractions.
C# Code for Multiplying Fractions - Class File
namespace Algebra
{
class MultiplyFraction
{
protected List<int> numerators = new List<int>();
protected List<int> denominators = new List<int>();
protected int[] answer = { 1, 1 };
protected int n_index, d_index;
protected int trial_factor;
protected bool mutual_factor;
public MultiplyFraction(List<int> num, List<int> denom)
{
numerators = num;
denominators = denom;
trial_factor = 0;
n_index = 0;
d_index = 0;
foreach (int n in numerators)
{
if (n > trial_factor)
{
trial_factor = n;
}
}
foreach (int d in denominators)
{
if (d > trial_factor)
{
trial_factor = d;
}
}
}
public int[] doMultiply()
{
// STEP 3:
// We are counting down to test for mutual factors
while (trial_factor > 1)
{
// STEP 1:
// iterate through numerators and check for factors
while (n_index < numerators.Count)
{
mutual_factor = false;
if ((numerators[n_index] % trial_factor) == 0)
{ // do we have a factor
// iterate through denominators and check for factors
while (d_index < denominators.Count)
{
if ((denominators[d_index] % trial_factor) == 0)
{ // is this factor mutual?
mutual_factor = true;
break; // stop as soon as we find a mutual factor so preserve the corresponding index
}
d_index++;
}
break; // stop as soon as we find a mutual factor so as preserve the corresponding index
}
n_index++;
}
// STEP 2:
// where we have a mutual factor
if (mutual_factor)
{
numerators[n_index] = numerators[n_index] / trial_factor;
denominators[d_index] = denominators[d_index] / trial_factor;
continue; // continue with next iteration repeating the current value of trial_factor
}
n_index = 0;
d_index = 0;
trial_factor--;
}
for (int i = 0; i < numerators.Count; i++)
{
answer[0] *= numerators[i];
answer[1] *= denominators[i];
}
return answer;
}
}
}
C# Code for Multiplying Fractions - Main Class
using System.Collections;
using System.Collections.Generic;
namespace Algebra
{
class Program
{
static void Main(string[] args)
{
Console.WriteLine("Welcome to our demonstration sequels");
Console.WriteLine("Hope you enjoy (and follow) the lessons.");
Console.WriteLine("\r\n");
/*
* Multiplying fractions
*/
List<int> numerators = new List<int>();
numerators.Add(16);
numerators.Add(20);
numerators.Add(27);
numerators.Add(20);
List<int> denominators = new List<int>();
denominators.Add(9);
denominators.Add(9);
denominators.Add(640);
denominators.Add(7);
Console.WriteLine(" Solving:");
// Print as fraction
foreach (int n in numerators)
{
Console.Write(String.Format("{0,13}", n));
}
Console.Write(Environment.NewLine + String.Format("{0,12}", " "));
for (int i = 0; i < numerators.Count - 1; i++)
{
Console.Write(String.Format("{0}", "- X "));
}
Console.WriteLine(String.Format("{0,1}", "-"));
foreach (int d in denominators)
{
Console.Write(String.Format("{0,13}", d));
}
Console.WriteLine();
// use the MultiplyFraction class
MultiplyFraction mul_fract = new MultiplyFraction(numerators, denominators);
int[] solution = mul_fract.doMultiply();
Console.WriteLine(Environment.NewLine);
Console.WriteLine(String.Format("{0,25}", solution[0]));
Console.WriteLine(String.Format("{0,25}", "Answer = -"));
Console.WriteLine(String.Format("{0,25}", solution[1]));
}
}
}