{"id":1603,"date":"2019-12-25T06:06:09","date_gmt":"2019-12-25T05:06:09","guid":{"rendered":"http:\/\/xmau.com\/wp\/ilpost\/?p=1603"},"modified":"2019-12-19T16:43:17","modified_gmt":"2019-12-19T15:43:17","slug":"quizzini-per-natale-2019","status":"publish","type":"post","link":"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/","title":{"rendered":"Problemini per Natale 2019"},"content":{"rendered":"<p>\u00c8 Natale, tornano i problemini&#8230; e quest&#8217;anno tornano quelli relativi al numero che corrisponde all&#8217;anno prossimo, con la soluzione che verr\u00e0 postata, assieme alle fonti per i problemi e per le soluzioni, il 31 dicembre; in questo modo potete forse evitare la solita tombola :-) Attenzione! L&#8217;ultimo problema non \u00e8 facilissimo.<\/p>\n<p><b><big>1. 2020 in tono minore<\/big><\/b><br \/>\nQual \u00e8 il numero pi\u00f9 grande che potete ottenere se prendete le cifre 2020 e senza cambiarne l&#8217;ordine aggiungete a piacere le quattro operazioni aritmetiche di base, spazi e parentesi? Beh, \u00e8 2020. Se fosse permesso l&#8217;elevamento a potenza avremmo 20<sup>20<\/sup>, ma niente da fare. E qual \u00e8 invece il numero pi\u00f9 piccolo che potete ottenere?<br \/>\n<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1617\" data-permalink=\"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/q431a\/\" data-orig-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q431a.png?fit=452%2C109&amp;ssl=1\" data-orig-size=\"452,109\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"q431a\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q431a.png?fit=452%2C109&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q431a.png?resize=452%2C109\" alt=\"\" width=\"452\" height=\"109\" class=\"aligncenter size-full wp-image-1617\" srcset=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q431a.png?w=452&amp;ssl=1 452w, https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q431a.png?resize=300%2C72&amp;ssl=1 300w\" sizes=\"auto, (max-width: 452px) 100vw, 452px\" \/><!-- La risposta non \u00e8 -2020, perch\u00e9 ha un meno unario e non un simbolo di sottrazione --><\/p>\n<p><b><big>2. Da 1 a 10<\/big><\/b><br \/>\nPartite dalla lista 1 2 3 4 5 6 7 8 9 10 e inserite a piacere i simboli delle quattro operazioni oppure parentesi per comporre un&#8217;operazione che vi faccia ottenere 2020. Non siete obbligati a mettere simboli ovunque: se volete partire con 1234 o finire con 910, va benissimo.<br \/>\n<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1618\" data-permalink=\"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/q432a\/\" data-orig-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q432a.png?fit=520%2C68&amp;ssl=1\" data-orig-size=\"520,68\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"q432a\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q432a.png?fit=520%2C68&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q432a.png?resize=520%2C68\" alt=\"\" width=\"520\" height=\"68\" class=\"aligncenter size-full wp-image-1618\" srcset=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q432a.png?w=520&amp;ssl=1 520w, https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q432a.png?resize=300%2C39&amp;ssl=1 300w\" sizes=\"auto, (max-width: 520px) 100vw, 520px\" \/><!-- A parte il 10, ci sono solo due numeri di due cifre. --><\/p>\n<p><b><big>3. Alla radice<\/big><\/b><br \/>\nQuanto vale la somma qui raffigurata?<br \/>\n<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1619\" data-permalink=\"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/q433a\/\" data-orig-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q433a.png?fit=435%2C42&amp;ssl=1\" data-orig-size=\"435,42\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"q433a\" data-image-description=\"\" data-image-caption=\"&lt;p&gt;1\/(1 + \u221a2) + 1\/(\u221a2 + \u221a3) + &amp;#8230; + 1\/(\u221a2019 + \u221a2020)&lt;\/p&gt;\n\" data-large-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q433a.png?fit=435%2C42&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q433a.png?resize=435%2C42\" alt=\"1\/(1 + \u221a2) + 1\/(\u221a2 + \u221a3) + ... + 1\/(\u221a2019 + \u221a2020)\" width=\"435\" height=\"42\" class=\"aligncenter size-full wp-image-1619\" srcset=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q433a.png?w=435&amp;ssl=1 435w, https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q433a.png?resize=300%2C29&amp;ssl=1 300w\" sizes=\"auto, (max-width: 435px) 100vw, 435px\" \/><!-- Togliete le radici dai denominatori. --><\/p>\n<p><b><big>4. Iterazioni<\/big><\/b><br \/>\n\u00c8 data la funzione <i>f<\/i>(<i>x<\/i>) = (1+<i>x<\/i>)\/(1&minus;<i>x<\/i>). Qual \u00e8 il valore dell&#8217;espressione qui sotto, dove la graffa significa che ci sono 2020 iterazioni della funzione <i>f<\/i>?<br \/>\n<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1626\" data-permalink=\"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/q434a\/\" data-orig-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q434a.png?fit=249%2C75&amp;ssl=1\" data-orig-size=\"249,75\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"q434a\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q434a.png?fit=249%2C75&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q434a.png?resize=249%2C75\" alt=\"\" width=\"249\" height=\"75\" class=\"aligncenter size-full wp-image-1626\" \/><!-- Calcolate le prime iterazioni dela funzione. --><\/p>\n<p><b><big>5. Soldi<\/big><\/b><br \/>\nAl corso di Economia della Condivisione, 2020 monete vengono divise in un certo modo tra gli studenti, e si chiede loro di scambiarsele secondo questa regola: quando due studenti si incontrano, mettono insieme le loro monete e se le dividono in parti uguali, mettendone una nella Cassa della Classe nel caso il totale sia dispari. Dopo (tanti&#8230;) scambi, gli studenti scoprono che tutte le monete sono finite nella Cassa. Qual \u00e8 il numero minimo possibile di studenti nella classe perch\u00e9 ci\u00f2 possa avvenire?<br \/>\n<img data-recalc-dims=\"1\" loading=\"lazy\" decoding=\"async\" data-attachment-id=\"1633\" data-permalink=\"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/q435a\/\" data-orig-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q435a.png?fit=300%2C300&amp;ssl=1\" data-orig-size=\"300,300\" data-comments-opened=\"1\" data-image-meta=\"{&quot;aperture&quot;:&quot;0&quot;,&quot;credit&quot;:&quot;&quot;,&quot;camera&quot;:&quot;&quot;,&quot;caption&quot;:&quot;&quot;,&quot;created_timestamp&quot;:&quot;0&quot;,&quot;copyright&quot;:&quot;&quot;,&quot;focal_length&quot;:&quot;0&quot;,&quot;iso&quot;:&quot;0&quot;,&quot;shutter_speed&quot;:&quot;0&quot;,&quot;title&quot;:&quot;&quot;,&quot;orientation&quot;:&quot;0&quot;}\" data-image-title=\"q435a\" data-image-description=\"\" data-image-caption=\"\" data-large-file=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q435a.png?fit=300%2C300&amp;ssl=1\" src=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q435a.png?resize=300%2C300\" alt=\"\" width=\"300\" height=\"300\" class=\"aligncenter size-full wp-image-1633\" srcset=\"https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q435a.png?w=300&amp;ssl=1 300w, https:\/\/i0.wp.com\/xmau.com\/wp\/ilpost\/wp-content\/uploads\/sites\/4\/2019\/12\/q435a.png?resize=150%2C150&amp;ssl=1 150w\" sizes=\"auto, (max-width: 300px) 100vw, 300px\" \/><!-- Ci deve essere almeno uno studente che parte senza monete. Lavorate all'indietro sul numero massimo di monete con due, tre, ... studenti --><\/p>\n","protected":false},"excerpt":{"rendered":"<p>Cinque problemini matematici che hanno a che fare con il 2020 <a href=\"https:\/\/xmau.com\/wp\/ilpost\/2019\/12\/25\/quizzini-per-natale-2019\/\">Continue reading <span class=\"meta-nav\">&rarr;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_lmt_disableupdate":"","_lmt_disable":"","jetpack_post_was_ever_published":false,"_jetpack_newsletter_access":"","_jetpack_dont_email_post_to_subs":false,"_jetpack_newsletter_tier_id":0,"_jetpack_memberships_contains_paywalled_content":false,"_jetpack_memberships_contains_paid_content":false,"activitypub_content_warning":"","activitypub_content_visibility":"","activitypub_max_image_attachments":4,"activitypub_interaction_policy_quote":"anyone","activitypub_status":"","footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[1],"tags":[129],"class_list":["post-1603","post","type-post","status-publish","format-standard","hentry","category-uncategorized","tag-quizzini"],"modified_by":".mau.","jetpack_publicize_connections":[],"jetpack_featured_media_url":"","jetpack_sharing_enabled":true,"jetpack_shortlink":"https:\/\/wp.me\/p6hpX6-pR","jetpack-related-posts":[{"id":922,"url":"https:\/\/xmau.com\/wp\/ilpost\/2016\/12\/25\/problemini-per-natale-2016\/","url_meta":{"origin":1603,"position":0},"title":"Problemini per Natale 2016","author":".mau.","date":"25\/12\/2016","format":false,"excerpt":"Ecco qua gli usuali cinque problemini che possono essere usati al posto della tombola natalizia, tutti basati sul 2017. 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