Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
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.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

fractions and non-similar denominator.

Problem Solving — algebra and arithmetic
Expert replies
by mist3rh » Mon Jun 21, 2010 5:39 am
Okay -this is really sad that I am asking this question, I cannot remember a quicker way that i used back in school days to add fractions with different denominators. One question I am solving in the OG requires two fractions be added. That itself is not the answer or the purpose of the question, rather just one part of the question. And given there are only 2 minutes or so to solve the problem, this is going to be a nightmare if i dont find an easy way out.

So fraction being added is 1/15 + 1/18. Can anyone comment as to how this will be solved the quickest possible manner. 18*15 way of doing it is lengthy and would give a bigger multiple to struggle with.
Join the discussion
Source: — Quantitative Reasoning |

by amising6 » Mon Jun 21, 2010 5:50 am
mist3rh wrote:Okay -this is really sad that I am asking this question, I cannot remember a quicker way that i used back in school days to add fractions with different denominators. One question I am solving in the OG requires two fractions be added. That itself is not the answer or the purpose of the question, rather just one part of the question. And given there are only 2 minutes or so to solve the problem, this is going to be a nightmare if i dont find an easy way out.

So fraction being added is 1/15 + 1/18. Can anyone comment as to how this will be solved the quickest possible manner. 18*15 way of doing it is lengthy and would give a bigger multiple to struggle with.
dude only way yo u can do faster is find lcm do the normal way but try to speed up calculation
which you will have to develop with time

there is no shortcut to add fraction
even if there is one it will be very tough to get right answer go the traditional way
find lcm and do
wont take much time
Ideation without execution is delusion
Join the discussion

by intellijat » Mon Jun 21, 2010 6:37 am
mist3rh wrote:Okay -this is really sad that I am asking this question, I cannot remember a quicker way that i used back in school days to add fractions with different denominators. One question I am solving in the OG requires two fractions be added. That itself is not the answer or the purpose of the question, rather just one part of the question. And given there are only 2 minutes or so to solve the problem, this is going to be a nightmare if i dont find an easy way out.

So fraction being added is 1/15 + 1/18. Can anyone comment as to how this will be solved the quickest possible manner. 18*15 way of doing it is lengthy and would give a bigger multiple to struggle with.
hi......
as pointed by amising6 take the LCM route:
15=3*5
18=3*3*2
so lcm=3*3*2*5=90
or
15*18 can be easily multiplied as (10+5)*18=180+90=270
or
15*(20-2)=300-30=270
Join the discussion

by mist3rh » Mon Jun 21, 2010 6:46 am
Thanks guys...guess i may just have to become comfortable with having to calculate it like you mention. Quant questions are harder (in OG) than i thought- i wonder how those who manage to score 50 tend to get through these.
Join the discussion