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## Comment on

Multiplying by Doubling and Halving.## What a classic strategy!

## Thanks - glad you like it!

Thanks - glad you like it!

## Wow!! impressive

## Extremely useful technique.

## Excellent technique, will

## They will never teach you

## Thanks for taking the time to

Thanks for taking the time to say such nice things! It made my day!

Cheers,

Brent

## Brent, you are absolutely

## This technique only works for

## Good question.

Good question.

The technique works for all numbers, but it doesn't always make calculations easier.

For example, the product of 19 x 11 EQUALS the product of 38 x 5.5, but the second product isn't necessarily easier to calculate.

Conversely, the product of 18 x 4 EQUALS the product of 9 x 8. In this case the second product is probably easier to calculate.

As I mention in the video, the technique works really well when one value ends in 5.

For example, the product of 35 x 18 EQUALS the product of 70 x 9, and the second product is easier to calculate.

Cheers,

Brent

## GRE practice question

How to get in to this link?I joined with user ID .But it is showing "You are not authorised to read this forum."

## Sorry about that. A few

Sorry about that. A few months ago, ETS made the forum remove all official GRE questions. Looks like I forgot to remove that official question.