subtracting fractions with Different Denominators | Rationalising Fractions in Visual Basic
Learning how to subtract fractions in Visual Basic is an important step for junior secondary students who are beginning to
combine mathematics with coding. In this tutorial, we'll walk through the process of subtracting fractions with different denominators,
explain how to use the LCM (Lowest Common Multiple) method, and show you how to rationalise or canonise
fractions before subtraction. By the end, you'll be able to write a simple Visual Basic program to subtract fractions step by step,
giving you both a solid maths foundation and practical coding skills to implement libraries like the built-in Visual Basic fractions module.
Like with Adding Fractions in Visual Basic, fractional numbers are also rationalised before subtraction.
This means they are put in a form where their denominators become the same. This identical denominator is the LCM of the
previous denominators of all the separate fractions.
After this is done, the new numerators can then be subtracted.
Steps for Subtraction of Fractions with Different Denominators - Visual Basic Algorithm
The following steps will guide us in writing our Visual Basic code for subtracting fractions.
Let's illustrate these steps with the example fractional expression
7/4 - 2/5
Step 1:
Using the Find LCM in Visual Basic
class from the Primary Category, find the LCM of the denominators.
⇒ LCM of 4 & 5 = 20
Step 2:
In a turn by turn fashion, divide the found LCM from Step 1
by each denominator, multiplying the quotient by the corresponding numerator.
⇒
((7 x 5) - (2 x 4))/20
= (35 - 8)/20
Step 3:
Go ahead and subtract the numerators.
⇒
27/20
Create a new VB.Net class file; Project, Add Class.
Call it SubtractFraction.vb.
Optionally, Create a new VB.Net module file; Project, Add Module.
Call it SubtractFractionModule.vb.
Type out the adjoining Visual Basic (VB.Net) codes for subtracting fractions.
Note: You can instead comment out the VB.Net code in
the main module from the previous lesson or simply continue from where it stopped.
So! Visual Basic Fun Practice Exercise - Add Fractions
As a fun practice exercise, feel free to try out your own fractions with different numerators and denominators,
and see how the Visual Basic code divides those fractions.
VB.Net Code for Subtracting Fractions - Class File
Public Class SubtractFraction
Inherits AddFraction
Public Function doSubtract() As Dictionary(Of String, Integer)
canonizeFraction()
answer = new_numerators(0)
For count_off = 1 To new_numerators.Count - 1
answer -= new_numerators(count_off)
Next count_off
Dim send_back As New Dictionary(Of String, Integer)
send_back.Add("numerator", answer)
send_back.Add("denominator", lcm)
Return send_back
End Function
End Class
VB.Net Code for Subtracting Fractions - Main Module
Module Algebra_SubtractFraction
Sub Main()
Dim numerators = {9, 3, 5, 7}
Dim denominators = {2, 4, 12, 18}
Dim fractions As New Dictionary(Of String, Integer())
fractions.Add("numerators", numerators)
fractions.Add("denominators", denominators)
Console.WriteLine(" Solving:")
For Each numerator In fractions.Item("numerators")
Console.Write(String.Format("{0,13}", numerator))
Next
Console.Write(Environment.NewLine & String.Format("{0,12}", " "))
For wasted = 0 To numerators.Count - 2
Console.Write(String.Format("{0}", "- - "))
Next
Console.WriteLine(String.Format("{0,1}", "-"))
For Each denominator In fractions.Item("denominators")
Console.Write(String.Format("{0,13}", denominator))
Next
Console.WriteLine("")
Dim sub_fract As New SubtractFraction
sub_fract._init_(fractions)
Dim fraction = sub_fract.doSubtract()
Console.WriteLine(Environment.NewLine)
Console.WriteLine(String.Format("{0,25}", fraction.Item("numerator")))
Console.WriteLine(String.Format("{0,25}", "Answer = -"))
Console.WriteLine(String.Format("{0,25}", fraction.Item("denominator")))
End Sub
End Module
