<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0" xmlns:itunes="http://www.itunes.com/dtds/podcast-1.0.dtd" xmlns:googleplay="http://www.google.com/schemas/play-podcasts/1.0"><channel><title><![CDATA[Coffee and Proofs]]></title><description><![CDATA[Challenging math problems for adults!]]></description><link>https://www.coffeeandproofs.com</link><image><url>https://substackcdn.com/image/fetch/$s_!SJVE!,w_256,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd069faa6-e70d-4d2b-9ff6-f750ab8fa679_1024x1024.png</url><title>Coffee and Proofs</title><link>https://www.coffeeandproofs.com</link></image><generator>Substack</generator><lastBuildDate>Thu, 07 May 2026 18:01:00 GMT</lastBuildDate><atom:link href="https://www.coffeeandproofs.com/feed" rel="self" type="application/rss+xml"/><copyright><![CDATA[Coffee and Proofs]]></copyright><language><![CDATA[en]]></language><webMaster><![CDATA[coffeeandproofs@substack.com]]></webMaster><itunes:owner><itunes:email><![CDATA[coffeeandproofs@substack.com]]></itunes:email><itunes:name><![CDATA[Coffee and Proofs]]></itunes:name></itunes:owner><itunes:author><![CDATA[Coffee and Proofs]]></itunes:author><googleplay:owner><![CDATA[coffeeandproofs@substack.com]]></googleplay:owner><googleplay:email><![CDATA[coffeeandproofs@substack.com]]></googleplay:email><googleplay:author><![CDATA[Coffee and Proofs]]></googleplay:author><itunes:block><![CDATA[Yes]]></itunes:block><item><title><![CDATA[Coffee and Proofs: problem #1]]></title><description><![CDATA[from the 2000 AIME I, a tricky system of equations!]]></description><link>https://www.coffeeandproofs.com/p/coffee-and-proofs-problem-1</link><guid isPermaLink="false">https://www.coffeeandproofs.com/p/coffee-and-proofs-problem-1</guid><dc:creator><![CDATA[Coffee and Proofs]]></dc:creator><pubDate>Sun, 06 Jul 2025 17:29:46 GMT</pubDate><enclosure url="https://substackcdn.com/image/fetch/$s_!SJVE!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd069faa6-e70d-4d2b-9ff6-f750ab8fa679_1024x1024.png" length="0" type="image/jpeg"/><content:encoded><![CDATA[<p>Today&#8217;s inaugural problem is a bit of a warm-up. It&#8217;s from the 2000 AIME I. Try it out without looking up the solution!</p><div class="captioned-image-container"><figure><a class="image-link image2 is-viewable-img" target="_blank" href="https://substackcdn.com/image/fetch/$s_!33CS!,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png" data-component-name="Image2ToDOM"><div class="image2-inset"><picture><source type="image/webp" srcset="https://substackcdn.com/image/fetch/$s_!33CS!,w_424,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 424w, https://substackcdn.com/image/fetch/$s_!33CS!,w_848,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 848w, https://substackcdn.com/image/fetch/$s_!33CS!,w_1272,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 1272w, https://substackcdn.com/image/fetch/$s_!33CS!,w_1456,c_limit,f_webp,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 1456w" sizes="100vw"><img src="https://substackcdn.com/image/fetch/$s_!33CS!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png" width="915" height="294" data-attrs="{&quot;src&quot;:&quot;https://substack-post-media.s3.amazonaws.com/public/images/d9521ee6-160f-45bf-befa-40f27e306966_915x294.png&quot;,&quot;srcNoWatermark&quot;:null,&quot;fullscreen&quot;:null,&quot;imageSize&quot;:null,&quot;height&quot;:294,&quot;width&quot;:915,&quot;resizeWidth&quot;:null,&quot;bytes&quot;:32764,&quot;alt&quot;:null,&quot;title&quot;:null,&quot;type&quot;:&quot;image/png&quot;,&quot;href&quot;:null,&quot;belowTheFold&quot;:false,&quot;topImage&quot;:true,&quot;internalRedirect&quot;:&quot;https://www.coffeeandproofs.com/i/167654021?img=https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png&quot;,&quot;isProcessing&quot;:false,&quot;align&quot;:null,&quot;offset&quot;:false}" class="sizing-normal" alt="" srcset="https://substackcdn.com/image/fetch/$s_!33CS!,w_424,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 424w, https://substackcdn.com/image/fetch/$s_!33CS!,w_848,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 848w, https://substackcdn.com/image/fetch/$s_!33CS!,w_1272,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 1272w, https://substackcdn.com/image/fetch/$s_!33CS!,w_1456,c_limit,f_auto,q_auto:good,fl_progressive:steep/https%3A%2F%2Fsubstack-post-media.s3.amazonaws.com%2Fpublic%2Fimages%2Fd9521ee6-160f-45bf-befa-40f27e306966_915x294.png 1456w" sizes="100vw" fetchpriority="high"></picture><div class="image-link-expand"><div class="pencraft pc-display-flex pc-gap-8 pc-reset"><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container restack-image"><svg role="img" width="20" height="20" viewBox="0 0 20 20" fill="none" stroke-width="1.5" stroke="var(--color-fg-primary)" stroke-linecap="round" stroke-linejoin="round" xmlns="http://www.w3.org/2000/svg"><g><title></title><path d="M2.53001 7.81595C3.49179 4.73911 6.43281 2.5 9.91173 2.5C13.1684 2.5 15.9537 4.46214 17.0852 7.23684L17.6179 8.67647M17.6179 8.67647L18.5002 4.26471M17.6179 8.67647L13.6473 6.91176M17.4995 12.1841C16.5378 15.2609 13.5967 17.5 10.1178 17.5C6.86118 17.5 4.07589 15.5379 2.94432 12.7632L2.41165 11.3235M2.41165 11.3235L1.5293 15.7353M2.41165 11.3235L6.38224 13.0882"></path></g></svg></button><button tabindex="0" type="button" class="pencraft pc-reset pencraft icon-container view-image"><svg xmlns="http://www.w3.org/2000/svg" width="20" height="20" viewBox="0 0 24 24" fill="none" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round" class="lucide lucide-maximize2 lucide-maximize-2"><polyline points="15 3 21 3 21 9"></polyline><polyline points="9 21 3 21 3 15"></polyline><line x1="21" x2="14" y1="3" y2="10"></line><line x1="3" x2="10" y1="21" y2="14"></line></svg></button></div></div></div></a></figure></div><p>Next Sunday, we&#8217;ll email the answer, along with some useful nuggets for solving this sort of problem. And we&#8217;ll share the next problem. See you then &#9749;&#65039;</p><div class="subscription-widget-wrap-editor" data-attrs="{&quot;url&quot;:&quot;https://www.coffeeandproofs.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}" data-component-name="SubscribeWidgetToDOM"><div class="subscription-widget show-subscribe"><div class="preamble"><p class="cta-caption">Thanks for reading! Subscribe for free to receive new posts and support my work.</p></div><form class="subscription-widget-subscribe"><input type="email" class="email-input" name="email" placeholder="Type your email&#8230;" tabindex="-1"><input type="submit" class="button primary" value="Subscribe"><div class="fake-input-wrapper"><div class="fake-input"></div><div class="fake-button"></div></div></form></div></div>]]></content:encoded></item><item><title><![CDATA[Welcome to ☕️ Coffee and Proofs Σ]]></title><description><![CDATA[Sign up to get one fun & challenging math problem every Sunday morning.]]></description><link>https://www.coffeeandproofs.com/p/welcome-to-coffee-and-proofs</link><guid isPermaLink="false">https://www.coffeeandproofs.com/p/welcome-to-coffee-and-proofs</guid><dc:creator><![CDATA[Coffee and Proofs]]></dc:creator><pubDate>Mon, 30 Jun 2025 01:44:14 GMT</pubDate><enclosure url="https://substack-post-media.s3.amazonaws.com/public/images/ca67a056-3e2e-4194-98e5-3dd14ff9912a_1024x1024.png" length="0" type="image/jpeg"/><content:encoded><![CDATA[<p></p><p class="button-wrapper" data-attrs="{&quot;url&quot;:&quot;https://www.coffeeandproofs.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe now&quot;,&quot;action&quot;:null,&quot;class&quot;:null}" data-component-name="ButtonCreateButton"><a class="button primary" href="https://www.coffeeandproofs.com/subscribe?"><span>Subscribe now</span></a></p><p>Math is a weird thing. There is so much excitement to learn math through grade school, high school, and even college. But unless you&#8217;re studying math in grad school &amp; beyond, it&#8217;s rare for even high aptitude adults to keep their love of math alive.</p><p>&#8220;Coffee and Proofs&#8221; is an attempt to reinvigorate the joy of math for adults. Sign up and get ONE interesting math problem every Sunday morning. The problems will likely vary in difficulty, subject matter, etc. I may choose harder problems from competitions like the USAMO or IMO. OR I may throw in simpler puzzles that don&#8217;t require more than grade school math. Either way, they&#8217;ll be fun problems to play around with and investigate while having your Sunday morning coffee.</p><p>I&#8217;ll aim to share the solution the following Sunday, along with the next problem. And for now, I&#8217;m starting off with this newsletter. But let me know if you have other ideas for what &#8220;math puzzles for adults&#8221; could look like! I have some ideas like leaderboards, book recs, other resources for learning how to solve problems, etc for later down the road, if there&#8217;s enough interest here.</p><p>I&#8217;m no expert, and I&#8217;m far from a math genius. But I&#8217;ve grown even more of a love for math in adulthood. So I&#8217;ll be learning along with everyone else. </p><p>Sign up and get our first puzzle next week :)</p><div><hr></div><div class="subscription-widget-wrap-editor" data-attrs="{&quot;url&quot;:&quot;https://www.coffeeandproofs.com/subscribe?&quot;,&quot;text&quot;:&quot;Subscribe&quot;,&quot;language&quot;:&quot;en&quot;}" data-component-name="SubscribeWidgetToDOM"><div class="subscription-widget show-subscribe"><div class="preamble"><p class="cta-caption">Thanks for reading Coffee and Proofs! Subscribe for free to receive new posts and support my work.</p></div><form class="subscription-widget-subscribe"><input type="email" class="email-input" name="email" placeholder="Type your email&#8230;" tabindex="-1"><input type="submit" class="button primary" value="Subscribe"><div class="fake-input-wrapper"><div class="fake-input"></div><div class="fake-button"></div></div></form></div></div><p></p>]]></content:encoded></item></channel></rss>