Understanding the Math Behind Fraction Multiplication | Maths Explanation for Python Kids
Learning how to multiply fractions in Python 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 Python 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 Python.
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 Python
This Python 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 Python 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.
Step 3:
Repeat Steps 1 & 2 recursively until there are no
more common factors.
Create a new Python module file;
call it MultiplyFraction.py.
Type out the adjoining Python code for multiplying fractions.
Note: You can comment out the LowestTerm Python object
code in the main class from the previous lesson or simply continue from where it stopped.
So! Python 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 Python code multiplies those fractions.
Python Code for Multiplying Fractions - Module File
class TimesFraction:
def __init__(self, fractions):
self.numerators = fractions['numerators']
self.denominators = fractions['denominators']
self.trial_factor = 0
self.n_index = 0
self.d_index = 0
self.answer = [1, 1]
for numerator in self.numerators:
if numerator > self.trial_factor:
self.trial_factor = numerator
for denominator in self.denominators:
if denominator > self.trial_factor:
self.trial_factor = denominator
def doMultiply(self):
while self.trial_factor > 1:
while self.n_index < len(self.numerators):
self.mutual_factor = False
if self.numerators[self.n_index] % self.trial_factor == 0:
while self.d_index < len(self.denominators):
if self.denominators[self.d_index] % self.trial_factor == 0:
self.mutual_factor = True
break
self.d_index += 1
break
self.n_index += 1
if self.mutual_factor:
self.numerators[self.n_index] /= self.trial_factor
self.denominators[self.d_index] /= self.trial_factor
continue
self.n_index = 0
self.d_index = 0
self.trial_factor -= 1
for numerator in self.numerators:
self.answer[0] *= numerator
for denominator in self.denominators:
self.answer[1] *= denominator
return {'numerator':int(self.answer[0]), 'denominator':int(self.answer[1])}
Python Code for Multiplying Fractions - Main Class
from MultiplyFraction import TimesFraction
numerators = [16, 20, 27, 20]
denominators = [9, 9, 640, 7]
fractions = {'numerators':numerators, 'denominators':denominators}
print('\n Solving:\n')
for numerator in fractions['numerators']: print('{:13d}'.format(numerator), end='')
print('{}{:>12}'.format('\n', ' '), end='')
for wasted in range(len(numerators)-1): print('{}'.format('- X '), end='')
print('{:>1}'.format('-'))
for denominator in fractions['denominators']: print('{:13d}'.format(denominator), end='')
print('\n\n')
mul_fract = TimesFraction(fractions)
fraction = mul_fract.doMultiply()
print('{:25d}'.format(fraction['numerator']))
print('{:>25}'.format('Answer = -'))
print('{:25d}'.format(fraction['denominator']))
print('\n\n')
