![\"quick](\"https:\/\/www.manhattanprep.com\/gre\/wp-content\/uploads\/sites\/19\/2019\/12\/mprep-blogimages-wave1-38-1-e1576271443343.png\")
<\/p>\n<\/p>\n
Mastering GRE math means <\/span>challenging yourself to improve your executive reasoning<\/span><\/a>, on top of re-learning math rules you may not have seen for years. It\u2019s not always an easy process, but there are a <\/span>few<\/span><\/i> quick math tricks that might earn you some points!<\/span><\/p>\n <\/p>\n \u201cWhy would I memorize the perfect squares if I get to use a calculator on the test?\u201d Because of problems like this one:\u00a0<\/span><\/p>\n If (x – 17)\u00b2<\/span>\u00a0= 361, which of the following could be the value of x?<\/span><\/p>\n (A) -36<\/span><\/p>\n (B) -16<\/span><\/p>\n (C) -2<\/span><\/p>\n (D) 2<\/span><\/p>\n (E) 16<\/span><\/p>\n This problem isn\u2019t asking you to square a number. If it was, you would just use the calculator. Nonetheless, if you know your perfect squares up to 20\u00b2<\/span>, you might see a quick way to solve this one. The not-so-quick way is to FOIL the expression on the left side, subtract 361, then try to figure out some way to solve the quadratic. The quick way? If you know that 361 is 19\u00b2<\/span>, take the square root of both sides!<\/span><\/p>\n x – 17 = \u00b119<\/span><\/p>\n x = 17 \u00b1 19<\/span><\/p>\n x = -2 or 36<\/span><\/p>\n The same goes for the prime numbers (up to 50) and the decimal forms of \u215b, \u2159, \u2155, \u00bc, and \u2153. It isn\u2019t about calculating them, since you\u2019ve got a calculator for that. It\u2019s about recognizing them when they could save you time on a challenging problem.<\/span><\/p>\n When you do a Data Interpretation problem that divides up a population into groups, always check to see how large the total population is. Here\u2019s an example from the <\/span>5lb. Book of GRE Practice Problems<\/span><\/a>:\u00a0<\/span><\/p>\n If you don\u2019t notice the 557 in the title of the graph, you could waste time adding up the households unnecessarily. Look for the total when you first read the graph! On harder problems, missing the total can make you fall for trap answers as well as wasting time.\u00a0<\/span><\/p>\n This GRE math trick requires you to adopt two new habits. First, on every single GRE math problem, read all the way through to the very end before you start solving. In particular, read the part of the problem that tells you what you\u2019re solving for.\u00a0<\/span><\/p>\n A lot of the time, you\u2019ll be solving for something totally ordinary:\u00a0<\/span><\/p>\n What is the value of x?<\/span><\/i><\/p>\n How many donuts did May purchase?\u00a0<\/span><\/i><\/p>\n But sometimes, you\u2019ll be solving for something trickier:<\/span><\/p>\n What is the probability that it will rain on Thursday but not on Wednesday?<\/span><\/i><\/p>\n What fraction of the students who passed the final exam had perfect attendance?<\/span><\/i><\/p>\n How much greater is the cost of a muffin than the cost of a donut?\u00a0<\/span><\/i><\/p>\n Here\u2019s the second new habit: every time the \u201cquestion\u201d part of a GRE math problem is even a little bit complicated, write down exactly what you\u2019re solving for, and put a box around it, <\/span>before<\/span><\/i> you start solving. If you can, you might even simplify a bit:<\/span><\/p>\n prob(rain Thurs)*(1-prob(rain Weds))<\/span><\/p>\n perf. attendance AND passed exam \/ passed exam<\/span><\/p>\n muffin $ – donut $<\/span><\/p>\n This serves a few purposes. First, it makes sure you\u2019re reading thoroughly. Second, it can get you unstuck if you\u2019re stuck on a problem: if you aren\u2019t sure what to do next, check what you still need to solve for in order to answer the question. It\u2019s also a useful part of your guessing strategy. If you can\u2019t articulate exactly what you\u2019re solving for, you should probably <\/span>bail out on the problem and move on to the next one<\/span><\/a>.\u00a0<\/span><\/p>\n A lot of Quantitative Comparisons GRE problems, like this one, have an easy number as one of the two quantities:\u00a0<\/span><\/p>\n You can solve this problem by calculating the exact value of the other quantity, but the trick here is that you don\u2019t have to. There\u2019s often a way to decide whether the harder quantity is bigger or smaller than the easier one, without calculating its exact value. When you see a problem where just one quantity is a number, take a moment to consider whether you can get away with just comparing.\u00a0<\/span><\/p>\n It\u2019s possible on this problem, by the way! Since there are more juniors than seniors, the average score should be closer to the juniors\u2019 average than the seniors\u2019. Thus, the average is closer to 88 than to 92, which means it must be lower than 90.\u00a0<\/span><\/p>\n Once you plug something into your calculator, it\u2019s gone! You can\u2019t look back at it and double-check that you entered all of the numbers right. So, unless you\u2019re entering something exactly as it\u2019s written in the problem (and maybe even then), jot down exactly what you\u2019re going to plug into the calculator before you calculate. Then you can at least double-check your work for mistakes and make changes later on if you need to. This is especially true for <\/span>Data Interpretation problems<\/span><\/a>, where I like to write down what I\u2019m calculating twice: once in plain English, then once with the numbers I\u2019ll be using.\u00a0<\/span><\/p>\n If you\u2019re looking for a more methodical approach to studying for the GRE, check out this article on <\/span>how to study<\/span><\/a>. Want more math tricks? Try <\/span>\u201cGRE Math for People Who Hate Math,\u201d<\/span><\/a> where we break down some of the more obscure-looking things on the GRE quant section into easier terms. And as you accumulate helpful math tricks, write them down! Add a column to your <\/span>error log<\/span><\/a> for strategies like these, and review it just before test day to refresh your memory.\u00a0<\/span><\/p>\n Don\u2019t forget that you can attend the first session of any of our online or in-person GRE courses absolutely free. We\u2019re not kidding! <\/i><\/b>Check out our upcoming courses here<\/i><\/b><\/a>.<\/i><\/b><\/p>\n Chelsey Cooley<\/a> Mastering GRE math means challenging yourself to improve your executive reasoning, on top of re-learning math rules you may not have seen for years. It\u2019s not always an easy process, but there are a few quick math tricks that might earn you some points!<\/p>\n","protected":false},"author":127,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[421],"tags":[133,151,161],"yst_prominent_words":[1364874,1363465,1364189,1364887,1362627,1362701,1364860,1362787,1364884,1364890,1364886,1363461,1364869,1362634,1362669,1364883,1364885,1363199,1364882],"class_list":["post-12669","post","type-post","status-publish","format-standard","hentry","category-gre-quant-2","tag-gre","tag-gre-math","tag-gre-quant"],"_links":{"self":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts\/12669","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/users\/127"}],"replies":[{"embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/comments?post=12669"}],"version-history":[{"count":1,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts\/12669\/revisions"}],"predecessor-version":[{"id":12673,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/posts\/12669\/revisions\/12673"}],"wp:attachment":[{"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/media?parent=12669"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/categories?post=12669"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/tags?post=12669"},{"taxonomy":"yst_prominent_words","embeddable":true,"href":"https:\/\/www.manhattanprep.com\/gre\/wp-json\/wp\/v2\/yst_prominent_words?post=12669"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}Memorize your squares (and primes, and decimals)<\/b><\/h3>\n
Check the total<\/b><\/h3>\n
![\"quick](\"https:\/\/www.manhattanprep.com\/gre\/wp-content\/uploads\/sites\/19\/2019\/12\/quick-gre-math-tricks.png\")
<\/p>\nPut the answer in a box<\/b><\/h3>\n
Avoid QC calculations<\/b><\/h3>\n
![\"quick](\"https:\/\/www.manhattanprep.com\/gre\/wp-content\/uploads\/sites\/19\/2019\/12\/quick-gre-math-tricks-2.png\")
<\/p>\nWrite what you put into the calculator<\/b><\/h3>\n
What next?<\/b><\/h3>\n
\n![\"Chelsey](\"https:\/\/cdn2.manhattanprep.com\/gre\/wp-content\/uploads\/sites\/19\/2015\/11\/chelsey-cooley-150x150.jpg\" "\\"Chelsey")
<\/a>\u00a0is a Manhattan Prep instructor based in Seattle, Washington.<\/strong>\u00a0<\/em><\/i><\/b>Chelsey always followed her heart when it came to her education. Luckily, her heart led her straight to the perfect background for GMAT and GRE teaching: she has undergraduate degrees in mathematics and history, a master\u2019s degree in linguistics, a 790 on the GMAT, and a perfect 170Q\/170V on the GRE.\u00a0<\/em><\/i>Check out Chelsey\u2019s upcoming GRE prep offerings here<\/a>.<\/em><\/i><\/p>\n","protected":false},"excerpt":{"rendered":"