{"id":548308,"date":"2025-06-10T14:03:48","date_gmt":"2025-06-10T17:03:48","guid":{"rendered":"https:\/\/revistapesquisa.fapesp.br\/?p=548308"},"modified":"2025-06-10T14:03:48","modified_gmt":"2025-06-10T17:03:48","slug":"from-kumon-classes-to-first-scientific-article","status":"publish","type":"post","link":"https:\/\/revistapesquisa.fapesp.br\/en\/from-kumon-classes-to-first-scientific-article\/","title":{"rendered":"From Kumon classes to first scientific article"},"content":{"rendered":"<p>A 13-year-old student found an easy way to multiply numbers with repeating digits by nine. The theorem developed by Enzo de Oliveira Pimenta states that when multiplying a number formed by a digit that repeats x times\u2014for example, 3,333,333, in which the digit 3 repeats seven times\u2014by nine, you simply need to multiply the repeating digit by nine, which will give a two-digit number y (27, in this case). The result of the multiplication will be the first digit of y followed by x-1 nines and then by the second digit of y: 29,999,997, in our example. \u201cThe theorem is linked to the principle of finite induction and could help in teaching this mathematical concept,\u201d says Enzo\u2019s father, Marcos Pimenta, a mathematician at S\u00e3o Paulo State University (UNESP). The principle of finite induction is based on the assumption that a statement that is correct for one natural number is true for the next number. Enzo developed his theorem while studying a Kumon course. His father encouraged him to prove the formula and helped him write an article about it, published in the journal <em>Professor de Matem\u00e1tica Online<\/em> (<em>Impartial<\/em>, October 17).<\/p>\n","protected":false},"excerpt":{"rendered":"Student develops theorem that makes it simple to multiply numbers with repeating digits by nine","protected":false},"author":475,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_exactmetrics_skip_tracking":false,"_exactmetrics_sitenote_active":false,"_exactmetrics_sitenote_note":"","_exactmetrics_sitenote_category":0,"footnotes":""},"categories":[1651],"tags":[226,246],"coauthors":[785],"class_list":["post-548308","post","type-post","status-publish","format-standard","hentry","category-notes","tag-education","tag-mathematics"],"acf":[],"_links":{"self":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/548308","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/users\/475"}],"replies":[{"embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/comments?post=548308"}],"version-history":[{"count":1,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/548308\/revisions"}],"predecessor-version":[{"id":548310,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/posts\/548308\/revisions\/548310"}],"wp:attachment":[{"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/media?parent=548308"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/categories?post=548308"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/tags?post=548308"},{"taxonomy":"author","embeddable":true,"href":"https:\/\/revistapesquisa.fapesp.br\/en\/wp-json\/wp\/v2\/coauthors?post=548308"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}