BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

★★★★★5.0559 reviews
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
Included
Live EA class + 6 months of EA OnDemand
  • Expert-led weekly online sessions
  • EA Masterclass access between classes
View EA class & enroll
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

130-point score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Unit digit of 7^7777?

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Problem Solving |
User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pmFollowed by: 252 members
Thanked: 653 times

by papgust » Tue Feb 02, 2010 9:38 pm
You know that 7^x repeats unit digits every fourth index.

7^1 = 7
7^2 = 9
7^3 = 3
7^4 = 1
7^5 = 7 (Again)
..
..

Now take the power 7777 and mod it by 4 (As it repeats every fourth index)

7777 % 4 = 1. Remainder is 1.

Raise the base 7 to the power 1 i.e. remainder. 7^1 = 7

So, units digit of 7^7777 = 7
Last edited by papgust on Tue Feb 02, 2010 11:07 pm, edited 1 time in total.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
MBA Student
Posts: 403
Joined: Tue Dec 22, 2009 7:32 pmFollowed by: 22 members
Thanked: 98 times

by fibbonnaci » Tue Feb 02, 2010 10:45 pm
papgust wrote:

So, units digit of 7^7777 = 1
Papgust, i guess u meant to say units digit of 7^7777 = 7
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Community Manager
Posts: 1537
Joined: Mon Aug 10, 2009 6:10 pmFollowed by: 252 members
Thanked: 653 times

by papgust » Tue Feb 02, 2010 11:06 pm
Yup :) Sorry, a typo.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1