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## Comment on

3-Digit Odd Numbers## Shouldn't the 1st digit be

## In the solution, we selected

In the solution, we selected the units digit first. This can be accomplished in 2 ways.

My second task was to select a hundreds digit. Since I had already selected ONE digit for the units digit (and since repeated digits are not allowed), there were only 5 digits to choose from (the original 6 digits MINUS the 1 digit I selected to be the units digit)

Does that help?

## I am generally confused when

## In the MAJORITY of counting

In the MAJORITY of counting questions on the GRE, the Fundamental Counting Principle is all you need. However, there ARE times when you'll need to use some combinations. The following video addresses that very issue: https://www.greenlighttestprep.com/module/gre-counting/video/788

## Fayes question is similar to

## Our first step is to choose a

Our first step is to choose a digit (a SINGLE digit) to go in the units place. There are two ways to accomplish this step (we can choose EITHER 1 OR 5)

Once we have placed a SINGLE digit in the units position, there are 5 digits remaining. So, we can complete the next step in 5 ways.

Does that help?

Cheers,

Brent

## Hi brant generally, in India

Generally, in India these kind of questions are thought with the formulas of permutation and combination. Npr and Ncr

## Yes, many resources refer to

Yes, many resources refer to these questions as "Permutation and Combination questions."

I'm not a big fan of this term since it suggests that all counting questions can be solved using either combinations or permutations, when this is not so.

I ramble (on and on) about this in the following article: https://www.gmatprepnow.com/articles/combinations-and-non-combinations-%...

Cheers,

Brent

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