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#NumberTheory #LastTwoDigits

This is a standard question in Math Olympiad: finding the last two digits of a big number, usually represented as a^b.

In this video, we need to find the last tow digits of 3^{20211019}. The options are (A) 27 (B) 47 (C) 67 (D) 87.


The answers for the extension questions are as follows.
1. 9901
2. 9187



Please have a good try.

Please give it a try before looking at the answer and explanation.


0:00 Introduction
0:30 The question
0:48 Method 1
2:55 Method 2
4:50 Algebraic manipulation
7:41 Extensions



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A math problem will be solved and discussed on every TUESDAY. These problems are suitable for math enthusiasts, it helps in learning and sharpening skills in math Olympiad skill too.

Check it out and share to anyone who may like it. Please comment if you have any idea to improve the videos, or any alternative solutions to the problems.

Have fun and enjoy the problem solving!