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104 LearnersLast updated on September 11, 2025

Calculators are reliable tools for solving simple mathematical problems and advanced calculations like cryptography. Whether you’re coding, solving equations, or working on number theory, calculators will make your life easy. In this topic, we are going to talk about multiplicative inverse modulo calculators.
A multiplicative inverse modulo calculator is a tool to find the multiplicative inverse of a number under a given modulus.
In modular arithmetic, the multiplicative inverse of an integer 'a' is another integer 'x' such that (a * x) ≡ 1 (mod m). This calculator simplifies the process, making it faster and more accurate.
Given below is a step-by-step process on how to use the calculator:
Step 1: Enter the integer and modulus: Input the integer and the modulus into the given fields.
Step 2: Click on calculate: Click on the calculate button to find the inverse.
Step 3: View the result: The calculator will display the result instantly.
To calculate the multiplicative inverse of a number 'a' under modulus 'm', you need to find an integer 'x' such that: (a * x) ≡ 1 (mod m)
This can be found using the Extended Euclidean Algorithm, which can efficiently compute the inverse when 'a' and 'm' are coprime.
When using a multiplicative inverse modulo calculator, here are a few tips and tricks to help avoid common mistakes:
We may think that when using a calculator, mistakes will not happen, but it is possible to make errors when using a calculator.
What is the multiplicative inverse of 3 modulo 11?
Use the Extended Euclidean Algorithm: 3 * x ≡ 1 (mod 11) The inverse is 4 because (3 * 4) % 11 = 12 % 11 = 1.
Using the algorithm, the inverse of 3 under mod 11 is found to be 4, satisfying the condition (3 * 4) ≡ 1 (mod 11).
Find the multiplicative inverse of 10 modulo 17.
Use the Extended Euclidean Algorithm: 10 * x ≡ 1 (mod 17) The inverse is 12 because (10 * 12) % 17 = 120 % 17 = 1.
The algorithm shows that 12 is the inverse of 10 under mod 17, as (10 * 12) ≡ 1 (mod 17).
Calculate the multiplicative inverse of 7 modulo 13.
Use the Extended Euclidean Algorithm: 7 * x ≡ 1 (mod 13) The inverse is 2 because (7 * 2) % 13 = 14 % 13 = 1.
The result confirms the inverse of 7 under mod 13 is 2, with (7 * 2) ≡ 1 (mod 13).
Is there a multiplicative inverse for 9 modulo 12?
No inverse exists because 9 and 12 are not coprime (greatest common divisor is 3).
Since 9 and 12 share a common factor other than 1, no inverse exists for 9 under mod 12.
Find the multiplicative inverse of 8 modulo 15.
Use the Extended Euclidean Algorithm: 8 * x ≡ 1 (mod 15) The inverse is 2 because (8 * 2) % 15 = 16 % 15 = 1.
The calculation shows 2 is the inverse of 8 under mod 15, as (8 * 2) ≡ 1 (mod 15).
Seyed Ali Fathima S a math expert with nearly 5 years of experience as a math teacher. From an engineer to a math teacher, shows her passion for math and teaching. She is a calculator queen, who loves tables and she turns tables to puzzles and songs.
: She has songs for each table which helps her to remember the tables






