In the previous post, we asked a few questions to help us understand the various concepts in number systems by examples.

Here are Video Solutions to all these problems :).

- What happens when you multiply 3 even numbers? 2 even numbers and an odd number? 2 odd numbers and an even number? and 3 odd numbers?
- What happens when you multiply 'N' even numbers? and 'N' odd numbers
- Can product of 4 consecutive numbers be Odd?

We then asked the question: Whats the smallest number should be added to 156789 to make it divisible by 11?

To solve this problem, we need to understand divisibility tests by 11. This and the solution to the problem is explained in the video below.

Our Next question was: Whats the smallest number that should be added to 677 to make it divisible by 4, 5, and 11?

To solve this, its important to understand concepts of LCM. The question is solved with concepts below.

Our Next question was related to power cycles: What is the units digit of 729

^{99}?

Detailed solution with basic power cycles concept is below.

Our Last question was in advanced Power cycle: What will be the last 2 digits when 25

^{625}is multiplied by 3

^{75}?

Concept explanation with detailed solution is given below.

Do let us know what you think about these solutions.

We will be back with more a more detailed Number Systems Lesson in the next week.

In other news: TCS will be the official test partner for CAT the next 5 years. This was announced a few days back.