If you're enjoying my video course, help spread the word on Twitter.

- Video Course
- Video Course Overview
- General GMAT Strategies - 7 videos (free)
- Data Sufficiency - 16 videos (free)
- Arithmetic - 38 videos
- Powers and Roots - 36 videos
- Algebra and Equation Solving - 73 videos
- Word Problems - 48 videos
- Geometry - 42 videos
- Integer Properties - 38 videos
- Statistics - 20 videos
- Counting - 27 videos
- Probability - 23 videos
- Analytical Writing Assessment - 5 videos (free)
- Reading Comprehension - 10 videos (free)
- Critical Reasoning - 38 videos
- Sentence Correction - 70 videos
- Integrated Reasoning - 17 videos

- Study Guide
- Your Instructor
- Office Hours
- Extras
- Prices

## Comment on

Squaring Numbers Ending in 5## Does this work if the base is

## Yes. Keep in mind that x² = (

Yes. Keep in mind that x² = (-x)².

For example, 3² = 9, and (-3)² = 9.

Likewise, 35² = (-35)² = 1225, and 65² = (-65)² = 4225

## Sir, How can we Find Last 2

## The last (units) digit is

The last (units) digit is pretty straightforward, but in most cases, the last 2 digits is outside the scope of the GMAT.

## Does this technique is also

## Good question.

Good question.

The answer is no; the technique can't be extended to powers other than 2.

## I think this technique can

## That's correct; the technique

That's correct; the technique works on for numbers ending in 5 (thus the title :-)

## Majestic!

## Indeed :-)

Indeed :-)

## Amazing!

## Hi Brent,

I have a question regarding this problem https://gmatclub.com/forum/6-226675.html

Automatically I looked at cyclicity of numbers in which 4 has cyclicity of 2 and 6 has cyclicity of 1, meaning that 6⁴ - 4⁴ will end up with unit digits 6-6= 0 so the result must be ending with zero. However, we have several answer choices ending with zero. So now since the exponent is 4 which means that 6⁴ has 4 digits and 4⁴ has 4 digits then the answer is E.

Is my approach is valid?

## Question link: https:/

Question link: https://gmatclub.com/forum/6-226675.html

That's a perfectly valid approach. Nice work!!

## Add a comment