{"id":68,"date":"2012-08-25T00:37:21","date_gmt":"2012-08-25T00:37:21","guid":{"rendered":"http:\/\/www.oracletutoring.ca\/blog\/?p=68"},"modified":"2012-08-25T01:31:51","modified_gmt":"2012-08-25T01:31:51","slug":"divisibility-by-3-divisibility-by-9","status":"publish","type":"post","link":"https:\/\/www.oracletutoring.ca\/blog\/divisibility-by-3-divisibility-by-9\/","title":{"rendered":"Divisibility by 3, Divisibility by 9"},"content":{"rendered":"<p>During math tutoring, no matter what the level, the front line is arithmetic.<\/p>\n<p>In that spirit, here&#8217;s a handy trick to tell if\u00a0a number is divisible by 3:<\/p>\n<p>Add up the digits.\u00a0 If the <em>sum<\/em> is divisible\u00a0by 3, then so is\u00a0the original number.<\/p>\n<p>Example:\u00a0 consider the number 222.\u00a0 2+2+2=6.\u00a0 Since 6 is divisible by 3,\u00a0so is 222.\u00a0 (Many people\u00a0might not\u00a0expect that.)\u00a0 In fact, 222 \u00f7 3 = 74.\u00a0 (Check for yourself.)<\/p>\n<p>A similar law works for 9:\u00a0 if the digits add up to something\u00a0divisible by 9, then the original number is\u00a0also divisible by 9.<\/p>\n<p>Example:\u00a0 consider 414.\u00a0 4+1+4 = 9, so 414 is divisible by 9.\u00a0 So is 864, since 8+6+4=18, and 18 is of course divisible by 9.<\/p>\n<p>Of all the math tricks I know, these are two of the most useful.<\/p>\n<p>Jack of <a title=\"Oracle Tutoring by Jack and Diane\" href=\"http:\/\/www.oracletutoring.ca\">Oracle Tutoring by Jack and Diane<\/a>, Campbell River, BC.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>During math tutoring, no matter what the level, the front line is arithmetic. In that spirit, here&#8217;s a handy trick to tell if\u00a0a number is divisible by 3: Add up the digits.\u00a0 If the sum is divisible\u00a0by 3, then so &hellip;<\/p>\n<p class=\"read-more\"> <a class=\"more-link\" href=\"https:\/\/www.oracletutoring.ca\/blog\/divisibility-by-3-divisibility-by-9\/\"> <span class=\"screen-reader-text\">Divisibility by 3, Divisibility by 9<\/span> Read More &raquo;<\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[3],"tags":[],"class_list":["post-68","post","type-post","status-publish","format-standard","hentry","category-math"],"_links":{"self":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/68","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/comments?post=68"}],"version-history":[{"count":10,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/68\/revisions"}],"predecessor-version":[{"id":77,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/posts\/68\/revisions\/77"}],"wp:attachment":[{"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/media?parent=68"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/categories?post=68"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.oracletutoring.ca\/blog\/wp-json\/wp\/v2\/tags?post=68"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}