{"id":757,"date":"2020-10-02T01:46:01","date_gmt":"2020-10-02T01:46:01","guid":{"rendered":"http:\/\/themindpalace.in\/?p=757"},"modified":"2021-08-28T09:39:49","modified_gmt":"2021-08-28T09:39:49","slug":"divisibility-rule","status":"publish","type":"post","link":"https:\/\/themindpalace.in\/index.php\/2020\/10\/02\/divisibility-rule\/","title":{"rendered":"Playing with Numbers Part-2 Divisibility Rule."},"content":{"rendered":"\n<p><a href=\"#summary\">Summary of playing with numbers part2<\/a><\/p>\n\n\n\n<p><a href=\"#solved exercise\">Solved exercise of playing with numbers<\/a><\/p>\n\n\n\n<div class=\"wp-block-image\"><figure class=\"aligncenter size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"960\" height=\"720\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/10\/Slide1-3.jpg\" alt=\"\" class=\"wp-image-1127\" srcset=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/10\/Slide1-3.jpg 960w, https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/10\/Slide1-3-300x225.jpg 300w, https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/10\/Slide1-3-768x576.jpg 768w\" sizes=\"(max-width: 960px) 100vw, 960px\" \/><\/figure><\/div>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"summary\">Summary<\/h1>\n\n\n\n<p>It help us to check from which number the number is divisible without actually dividing.<\/p>\n\n\n\n<p>An integer a and integer b not equal to zero and there exist an integer c, such that AC is equal to b.we write a divided by b to indicate that a divides b *divisibility is a positive property.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#c11290\" class=\"has-inline-color\">Divisibility Rule for 2<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 2 if the one\u2019s digit is even. Therefore, any number that ends with 0,2,4,6, or 8 is divisible by 2.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example: 62,108,63564,70006&#8230;.<\/span><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#c21497\" class=\"has-inline-color\">Divisibility Rule for 3<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 3 if the sum of the digits is divisible by 3 <\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example:96 we have to add the digit 9+6=15<\/span><\/p>\n\n\n\n<p>15 is a multiple of 3, therefore 96 is divisible by 3.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#c21488\" class=\"has-inline-color\">Divisibility rule for 4<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 4 if the number formed by the last two digits is divisible by 4.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example: 124 last two digits in 124 or 24, 24 is multiple of 4 therefore 124 is divisible by 4.<\/span><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span style=\"color:#b6118d\" class=\"has-inline-color\">Divisibility rule for 5<\/span><\/h4>\n\n\n\n<p>A number is divisible by 5 if the last digit is 0 or 5.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example: 100, 455, 680&#8230;.<\/span><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#ce1493\" class=\"has-inline-color\">Divisibility rule for 6<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 6 if it is divisible by 2, 3.<\/p>\n\n\n\n<p>Lets look at the number 132<\/p>\n\n\n\n<ul><li>132 is an even number.<\/li><li>And, sum of the digits is 1 + 3 + 2=6<\/li><li>6 is a multiple of 3, therefore 132 is divisible by 6.<\/li><\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#c31a9f\" class=\"has-inline-color\">Divisibility rule for 7<\/span><\/strong><\/h4>\n\n\n\n<p>we check whether the number is divisible by 7 by following the given steps, take the last digit of the number double it subtract the doubled number from the remaining number* if the result is divisible by 7 ,then the number is divisible by 7.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example: 203<\/span><\/p>\n\n\n\n<ul><li>The last digit of 203 is 3<\/li><li>Double of 3 =3 X 2 = 6<\/li><li>Subtract 6 from 20, 20 \u2013 6 = 14<\/li><li>14 is multiple of 7 then the number 203 is divisible by 7<\/li><\/ul>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#c60f8c\" class=\"has-inline-color\">Divisibility rule for 8<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 8 if the last three digits divisible by 8<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example: 9640<\/span><\/p>\n\n\n\n<p>640 \u00f7 8 = 80 it\u2019s a multiple of 8<\/p>\n\n\n\n<p>Therefore 9640, is divisible by 8<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#ce1477\" class=\"has-inline-color\">Divisibility rule for 9<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 9, if the sum of the digits of the number is divisible by 9.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Examples: 3573 = 3 + 5 + 7 + 3 = 18<\/span><\/p>\n\n\n\n<p>18 is a multiple of 9 therefore 3573 is divisible by 9<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#b3095b\" class=\"has-inline-color\">Divisibility rule for 10<\/span><\/strong><\/h4>\n\n\n\n<p>A number is divisible by 10 if the number\u2019s &nbsp;units place is 0.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Examples: 35680 is divisible 10 because its one\u2019s place is 0<\/span><\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><strong><span style=\"color:#af0d56\" class=\"has-inline-color\">Divisibility rule for 11<\/span><\/strong><\/h4>\n\n\n\n<p>According to the divisibility rule of 11, we must subtract.The steps followed are, add the digits in odd places, add the digits in even place, find the difference between both of them. If answer is either zero or divisible by 11, then it is divisible.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example:&nbsp;&nbsp; 1353<\/span><\/p>\n\n\n\n<p>[1 + 5] \u2013 [ 3+3] = 6 -6 = 0 therefore the number is divisible by 11.<\/p>\n\n\n\n<h4 class=\"wp-block-heading\"><span style=\"color:#b20e63\" class=\"has-inline-color\">Odd  an Even places<\/span><\/h4>\n\n\n\n<h4 class=\"wp-block-heading\"><span style=\"color:#aa1062\" class=\"has-inline-color\">Divisibility Rule for 12<\/span><\/h4>\n\n\n\n<p>A number is divisible by 12 if it is divisible by both 3 and 4.<\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">Example: 384 is divisible by 12.<\/span><\/p>\n\n\n\n<p>3 + 8 + 4= 15 it\u2019s a multiple of 3,<\/p>\n\n\n\n<p>84 is divisible by 4 therefore the number 384 is divisible by 12.<\/p>\n\n\n\n<figure class=\"wp-block-embed is-type-video is-provider-youtube wp-block-embed-youtube wp-embed-aspect-16-9 wp-has-aspect-ratio\"><div class=\"wp-block-embed__wrapper\">\n<div class=\"epyt-video-wrapper\"><iframe loading=\"lazy\"  id=\"_ytid_56271\"  width=\"480\" height=\"270\"  data-origwidth=\"480\" data-origheight=\"270\" src=\"https:\/\/www.youtube.com\/embed\/ikIlL3p4fB8?enablejsapi=1&#038;autoplay=0&#038;cc_load_policy=0&#038;cc_lang_pref=&#038;iv_load_policy=1&#038;loop=0&#038;rel=1&#038;fs=1&#038;playsinline=0&#038;autohide=2&#038;theme=dark&#038;color=red&#038;controls=1&#038;disablekb=0&#038;\" class=\"__youtube_prefs__  epyt-is-override  no-lazyload\" title=\"YouTube player\"  allow=\"fullscreen; accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture; web-share\" referrerpolicy=\"strict-origin-when-cross-origin\" allowfullscreen data-no-lazy=\"1\" data-skipgform_ajax_framebjll=\"\"><\/iframe><\/div>\n<\/div><\/figure>\n\n\n\n<h1 class=\"wp-block-heading\" id=\"Exercise\"><strong><span class=\"has-inline-color has-vivid-purple-color\">Solved Examples<\/span><\/strong><\/h1>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-red-color\">Example 1:<\/span><\/strong><\/p>\n\n\n\n<p>Write the following list of numbers in the generalized form.<\/p>\n\n\n\n<p>a. 125 b. 76 c. 59 d. 895<\/p>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-purple-color\">Solution:<\/span><\/strong>Given numbers are 125, 76, 59, 895<\/p>\n\n\n\n<p>General form of 125 is as follows: 125 can be expressed as 100 + 20 + 5<\/p>\n\n\n\n<p>(1 x100) + (2 x10) + 5 is 125.<\/p>\n\n\n\n<p>76 = 70 + 6=( 7 x 10) + 6<\/p>\n\n\n\n<p>59 = 50 + 9= (5 x 10) + 9<\/p>\n\n\n\n<p>895 = 800 + 90 + 5= (8 x 100) + (9 x10 )+ 5.<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-red-color\">Example 2:<\/span><\/strong><\/p>\n\n\n\n<p><span style=\"color:#5e07df\" class=\"has-inline-color\">Prove that the following numbers satisfy the reversing the digits method<\/span>?<\/p>\n\n\n\n<p>a. 12  b. 756<\/p>\n\n\n\n<p><strong><span style=\"color:#1d723d\" class=\"has-inline-color\">Solution:<\/span><\/strong><\/p>\n\n\n\n<p>a. Given two-digit number is 12.<\/p>\n\n\n\n<p>Reverse of 12 is 21.<\/p>\n\n\n\n<p>12 + 21 = 33<\/p>\n\n\n\n<p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;<\/p>\n\n\n\n<p> &nbsp; 11) 3 3 (3<\/p>\n\n\n\n<p>&nbsp;&nbsp;   \u2013&nbsp; &nbsp;3 3<\/p>\n\n\n\n<p>&nbsp; &nbsp;  =&nbsp; &nbsp;0<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#3a0cd1\" class=\"has-inline-color\">b. Three digit number is 756<\/span><\/p>\n\n\n\n<p>Reverse of 756 is 657<\/p>\n\n\n\n<p>756 \u2013 657 = 99            <\/p>\n\n\n\n<p> 99) 9 9 (1<\/p>\n\n\n\n<p>   \u2013&nbsp; &nbsp;9 9<\/p>\n\n\n\n<p>    =&nbsp; &nbsp;0<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#c70f40\" class=\"has-inline-color\">Example 3<\/span><\/strong><\/p>\n\n\n\n<p>In a two-digit number, the digit in the units place is 4 times the digit in the tens place and the sum of the digits is equal to 10. What is the number?<\/p>\n\n\n\n<p><strong><span style=\"color:#108032\" class=\"has-inline-color\">Solution:<\/span><\/strong><\/p>\n\n\n\n<p>Let us take two digit number as \u2018ab\u2019<\/p>\n\n\n\n<p>b = 4 xa<\/p>\n\n\n\n<p>a + b = 10<\/p>\n\n\n\n<p>Substitute b = 4a in the above equation.<\/p>\n\n\n\n<p>a + 4 xa = 10<\/p>\n\n\n\n<p>5a = 10<\/p>\n\n\n\n<p>a = 2<\/p>\n\n\n\n<p>Substitute a = 2 in the equation to get b value.<\/p>\n\n\n\n<p>2 + b = 10<\/p>\n\n\n\n<p>b = 10 \u2013 2 = 8<\/p>\n\n\n\n<p>\u2234 The number is 28.<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-red-color\">Example 4:<\/span><\/strong><\/p>\n\n\n\n<p><span style=\"color:#d40b62\" class=\"has-inline-color\">Check is 195 divisible by 4 or not?<\/span><\/p>\n\n\n\n<p><strong><span style=\"color:#2d7a1a\" class=\"has-inline-color\">Solution:<\/span><\/strong><\/p>\n\n\n\n<p>Given divisor is 195 and dividend is 4<\/p>\n\n\n\n<p>The last digit of 195 is 5, which is not divisible by 4.<\/p>\n\n\n\n<p>Hence, 195 is not divisible by 4.<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span class=\"has-inline-color has-vivid-red-color\">Example 5:<\/span><\/strong><\/p>\n\n\n\n<p><span style=\"color:#0f15c5\" class=\"has-inline-color\">I<\/span><span style=\"color:#2c18e5\" class=\"has-inline-color\">n the given 3 \u00d7 3 grid, arrange the digits from 1 to 9 (without repetition) such that the sum of the numbers surrounding any cell is a multiple of the number in the cell.<\/span><\/p>\n\n\n\n<p><strong><span style=\"color:#206b15\" class=\"has-inline-color\">Solution:<\/span><\/strong><\/p>\n\n\n\n<p>The only way is provided here.<\/p>\n\n\n\n<figure class=\"wp-block-table\"><table><tbody><tr><td><strong>4<\/strong><\/td><td><strong>8<\/strong><\/td><td><strong>9<\/strong><\/td><\/tr><tr><td>1<\/td><td>3<\/td><td>7<\/td><\/tr><tr><td>5<\/td><td>6<\/td><td>2<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#eb0e45\" class=\"has-inline-color\">Exercise 1.1<\/span><\/strong><\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">1. Find the values of the letters in each of the following and give reasons for the steps involved.<\/span><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"88\" height=\"87\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/1.jpg\" alt=\"\" class=\"wp-image-2106\"\/><\/figure>\n\n\n\n<p><span style=\"color:#197224\" class=\"has-inline-color\">Solution:<\/span> we have  3   A<\/p>\n\n\n\n<p>                               +2     5<\/p>\n\n\n\n<p>                                 <strong><span class=\"has-inline-color has-vivid-red-color\"> B     2<\/span><\/strong><\/p>\n\n\n\n<p>A+5, we get a unit digit 2<\/p>\n\n\n\n<p>For A =7 we get 7+5=12<\/p>\n\n\n\n<p>the value of B=1(Carried on)<\/p>\n\n\n\n<p>+3+2=6<\/p>\n\n\n\n<p>Thus the addition is  3   7<\/p>\n\n\n\n<p>                                    +2    5<\/p>\n\n\n\n<p>                                     <span class=\"has-inline-color has-vivid-red-color\"> 6     2<\/span><\/p>\n\n\n\n<p>Hence A=7 and B=6<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#d80c38\" class=\"has-inline-color\">Question 2<\/span><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"100\" height=\"90\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/2.png\" alt=\"\" class=\"wp-image-2107\"\/><\/figure>\n\n\n\n<p>Solution We have      4     A<\/p>\n\n\n\n<p>                                 +  9       8<\/p>\n\n\n\n<p>                               <span class=\"has-inline-color has-vivid-red-color\">   C  B      3<\/span><\/p>\n\n\n\n<p>A+8 We get a unit digit 3<\/p>\n\n\n\n<p>For A=5, we get 5+8=13<\/p>\n\n\n\n<p>The value of B and C= 1(Carried on)+4 +9=14<\/p>\n\n\n\n<p>Thus the addition is   4     5<\/p>\n\n\n\n<p>                                  +  9        8<\/p>\n\n\n\n<p>                                     <span class=\"has-inline-color has-vivid-red-color\">1    2    3<\/span><\/p>\n\n\n\n<p>Hence, A=5, B=4 and C=1<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#b90f3c\" class=\"has-inline-color\"><strong>Question 3<\/strong><\/span><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"71\" height=\"90\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/3.jpg\" alt=\"\" class=\"wp-image-2108\"\/><\/figure>\n\n\n\n<p><span style=\"color:#13692f\" class=\"has-inline-color\">Solution<\/span><\/p>\n\n\n\n<p>We have 1   A<\/p>\n\n\n\n<p>                x     A<\/p>\n\n\n\n<p>             <span class=\"has-inline-color has-vivid-red-color\"> 9       A<\/span><\/p>\n\n\n\n<p>AxA=A which is time for A =1 or 6<\/p>\n\n\n\n<p>For 1&#215;1=1 is not 9<\/p>\n\n\n\n<p>for A=6, we get 6&#215;6=36<\/p>\n\n\n\n<p>Ax1=6&#215;1+3(Carried on)<\/p>\n\n\n\n<p>=9<\/p>\n\n\n\n<p>Hence A=6<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#e71029\" class=\"has-inline-color\">Question 4.<\/span><\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"87\" height=\"86\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/44.jpg\" alt=\"\" class=\"wp-image-2110\"\/><\/figure>\n\n\n\n<p><span style=\"color:#0f762c\" class=\"has-inline-color\"><strong>Solution:<\/strong><\/span> 3+A=6<\/p>\n\n\n\n<p>A=6-3=3<\/p>\n\n\n\n<p>=2+1(Carried on)<\/p>\n\n\n\n<p>A=2<\/p>\n\n\n\n<p>Now 7+B=a number with unit place 2i.e,12<\/p>\n\n\n\n<p>There B=12-7=5<\/p>\n\n\n\n<p>Thus the addition = 2     5<\/p>\n\n\n\n<p>                                 + 3     7<\/p>\n\n\n\n<p>                                 <span class=\"has-inline-color has-vivid-red-color\">  6      2<\/span><\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#b61426\" class=\"has-inline-color\">&nbsp;<strong>Question 5<\/strong><\/span><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"83\" height=\"85\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/5n.jpg\" alt=\"\" class=\"wp-image-2111\"\/><\/figure>\n\n\n\n<p><span style=\"color:#366819\" class=\"has-inline-color\"><strong>Solution<\/strong><\/span><\/p>\n\n\n\n<p>3xb=b<\/p>\n\n\n\n<p>=B=D<\/p>\n\n\n\n<p>3xA=CA<\/p>\n\n\n\n<p>\u21d2 3 \u00d7 5 = 15<br>Thus A = 5 and C = 1<br>Hence A = 5, B = 0 and C = 1<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#ba0b31\" class=\"has-inline-color\">Question 6.<\/span><\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"85\" height=\"87\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/10.jpg\" alt=\"\" class=\"wp-image-2112\"\/><\/figure>\n\n\n\n<p>5 \u00d7 B = B<br>\u21d2 B = 0 or 5<br>5 \u00d7 A = CA<br>5 \u00d7 5 = 25<br>Only possible when B = 0<br>Thus A = 5 and C = 2<br>Hence A = 5, B = 0 and C = 2<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#f10f2d\" class=\"has-inline-color\">Question 7.<\/span><\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"89\" height=\"93\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/7.jpg\" alt=\"\" class=\"wp-image-2113\"\/><\/figure>\n\n\n\n<p><span style=\"color:#1e6d23\" class=\"has-inline-color\"><strong>Solution:<\/strong><\/span> B \u00d7 6 = B<br>6 \u00d7 4 = 24 \u2192 B = 4 and 2 is carried to<br>6 \u00d7 A = BB<br>\u21d2 6 \u00d7 7 = 42 + 2 (carried on) = 44<br>Thus B = 7<br>Hence A = 7 and B = 4<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#f30b5c\" class=\"has-inline-color\"><strong>Question 8<\/strong><\/span><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"89\" height=\"86\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/8.jpg\" alt=\"\" class=\"wp-image-2114\"\/><\/figure>\n\n\n\n<p><strong><span style=\"color:#1c6f43\" class=\"has-inline-color\">Solution<\/span><\/strong>:1 + B = 0<br>1 + 9 = 10 \u2192 unit digit is 0 and 1 is carried to A<br>+ 1 +1 (carried on) = B = 9<br>A + 2 = 9 \u21d2 A = 9 \u2013 2 = 7<br>Hence A = 7 and B = 9<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#d80a26\" class=\"has-inline-color\">Question 9.<\/span><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"113\" height=\"88\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/9.jpg\" alt=\"\" class=\"wp-image-2115\"\/><\/figure>\n\n\n\n<p><strong><span style=\"color:#226c1e\" class=\"has-inline-color\">Solution:<\/span><\/strong><\/p>\n\n\n\n<p>B + 1 = 8 \u21d2 B = 8 \u2013 1 = 7<br>A + B = a number with unit digit 1<br>A + B = 11<br>\u21d2 A + 7 = 11<br>\u21d2 A = 11 \u2013 7 = 4 (1 Carried to)<\/p>\n\n\n\n<p>Now 1 carried on + 2 + A = B<br>3 + A = 7<br>\u21d2 A = 7 \u2013 3 = 4<br>Hence A = 4, B = 7<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#c50e24\" class=\"has-inline-color\">Question 10.<\/span><\/strong><\/p>\n\n\n\n<figure class=\"wp-block-image size-large\"><img loading=\"lazy\" decoding=\"async\" width=\"109\" height=\"87\" src=\"https:\/\/themindpalace.in\/wp-content\/uploads\/2020\/12\/100.jpg\" alt=\"\" class=\"wp-image-2116\"\/><\/figure>\n\n\n\n<p><strong><span style=\"color:#2d701c\" class=\"has-inline-color\">Solution:<\/span><\/strong>9 = A + B<br>9 = 1 + 8 or 2 + 7 or 3 + 6 or 4 + 5 or 8 + 1 or 7 + 2 or 6 + 3 or 5 + 4 or 0 + 9 or 9 + 0<br>Now 0 is required at unit place<\/p>\n\n\n\n<p>2 + A = 10<br>\u21d2 A = 10 \u2013 2 = 8<br>B = 9 \u2013 8 = 1<br>1 + 6 + 1 (carried on) = A = 8<br>Hence A = 8 and B = 1.<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><strong><span style=\"color:#e01249\" class=\"has-inline-color\">Exercise 1.2<\/span><\/strong><\/p>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">1. If 21y5 is a multiple of 9, where y is a digit, what is the value of y?<\/span><\/p>\n\n\n\n<p><span style=\"color:#166d37\" class=\"has-inline-color\"><strong>Solution:<\/strong><\/span><\/p>\n\n\n\n<p>A number is divisible by 9 if the sum of its digits is also divisible by 9.<br>Sum of the digits of 21y5 = 2 + 1 +y + 5 = 8 + y<br>(8 + y) \u00f7 9 = 1<br>\u21d2 8 + y = 9<br>\u21d2 y = 9 \u2013 8 = 1<br>Hence, the required value of y = 1.<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">2. If 31z5 is a multiple of 9, where z is a digit, what is the value of z?<\/span><\/p>\n\n\n\n<p><span style=\"color:#1f7e2a\" class=\"has-inline-color\"><strong>Solution:<\/strong><\/span> A number is a multiple of 9 when the sum of its digits is also divisible by 9.<br>Sum of the digits of 31z5 = 3 + 1 + z + 5<\/p>\n\n\n\n<p>3 + 1 + 2 + 5 = 9k where k is an integer.<br>For k = 1,<br>3 + 1 + z + 5 = 9<br>\u21d2 z = 9 \u2013 9 = 0<\/p>\n\n\n\n<p>For k = 2,<br>3 + 1 + z + 5 = 18<br>\u21d2 z = 18 \u2013 9 = 9<br>k = 3 is not possible because 3 + 1 + z + 5 = 27<br>\u21d2 z = 27 \u2013 9 = 18 which is not a digit.<br>Hence the required value of z is 0 or 9<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span style=\"color:#e40f28\" class=\"has-inline-color\">3. If 24x is a multiple of 3, where x is a digit, what is the value of x?<\/span><\/p>\n\n\n\n<p><span style=\"color:#2f6c1d\" class=\"has-inline-color\"><strong>Solution:<\/strong><\/span> Since 24x is a multiple of 3, the sum of digits 6 + x is a multiple of 3; so 6 + x is one of these numbers; 0, 3, 6, 12, 15, 18, \u2026\u2026..<br>6 + x = 3k where k is any integer.<br>For k = 0,<br>6 + x = 3 \u00d7 0<br>\u21d2 6 + x = 0<\/p>\n\n\n\n<p>x = -6. Not possible<br><span style=\"color:#f809d0\" class=\"has-inline-color\">For k = 1,<\/span><br>6 + x = 3 \u00d7 1<br>\u21d2 6 + x = 3<br>\u21d2 x = 3 \u2013 6 = -3. Not possible<\/p>\n\n\n\n<p><span style=\"color:#df06cd\" class=\"has-inline-color\">For k = 2,<\/span><br>6 + x = 3 \u00d7 2<br>\u21d2 6 + x = 6<br>\u21d2 x = 6 \u2013 6 = 0<br>2 + 4 + 0 = 6 multiple of 3<\/p>\n\n\n\n<p><span style=\"color:#e70cc2\" class=\"has-inline-color\">For k = 3,<\/span><br>6 + x = 3 \u00d7 3<br>\u21d2 x = 9 \u2013 6 = 3<br>2 + 4 + 3 = 9 multiple of 3<\/p>\n\n\n\n<p><span style=\"color:#f30dc1\" class=\"has-inline-color\">For k = 4,<\/span><br>6 + x = 3 \u00d7 4<br>\u21d2 6 + x = 12<br>\u21d2 x = 12 \u2013 6 = 6<br>2 + 4 + 6 = 12 which is multiple of 3<\/p>\n\n\n\n<p><span style=\"color:#e50aa0\" class=\"has-inline-color\">For k = 5,<\/span><br>6 + x = 3 \u00d7 5<br>\u21d2 x = 15 \u2013 6 = 9<br>2 + 4 + 9 = 15 which is multiple of 3<\/p>\n\n\n\n<p><span style=\"color:#f40c9b\" class=\"has-inline-color\">For k = 6,<\/span><br>6 + x = 3 \u00d7 6<br>\u21d2 x = 18 \u2013 6 = 12 not possible as x is digit<br>Hence the required values of x are 0, 3, 6 or 9.<\/p>\n\n\n\n<hr class=\"wp-block-separator is-style-wide\"\/>\n\n\n\n<p><span class=\"has-inline-color has-vivid-purple-color\">4. If 31z5 is a multiple of 3, where z is a digit, what might be the value of z?<\/span><\/p>\n\n\n\n<p><span style=\"color:#125f21\" class=\"has-inline-color\"><strong>Solution<\/strong>:<\/span> A number is a multiple of 3 if the sum of its digits is divisible by 3.<br>3 + 1 + z + 5 = 3k where k is an integer<br>\u21d2 9 + z = 3k<br>\u21d2 z = 3k \u2013 9<\/p>\n\n\n\n<p>A number is a multiple of 3 if the sum of its digits is divisible by 3.<br>3 + 1 + z + 5 = 3k where k is an integer<br>\u21d2 9 + z = 3k<br>\u21d2 z = 3k \u2013 9<\/p>\n\n\n\n<p>For k = 4,<br>z = 3 \u00d7 4 \u2013 9 = 12 \u2013 9 = 3<br>9 + 3 = 12 multiple of 3<\/p>\n\n\n\n<p>For k = 6,<br>z = 3 \u00d7 6 \u2013 9 = 18 \u2013 9 = 9<br>9 + 9 = 18 multiple of 3<\/p>\n\n\n\n<p>For k = 7,<br>z = 3 \u00d7 7 \u2013 9 = 21 \u2013 9 = 12 not possible as z is a digit<br>Hence, the required values of 2 are 0, 3, 6 and 9.<\/p>\n\n\n\n<p>For k = 5,<br>z = 3 \u00d7 5 \u2013 9 = 15 \u2013 9 = 6<br>9 + 6 = 15 multiple of 3<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Summary of playing with numbers part2 Solved exercise of playing with numbers Summary It help us to check from which number the number is divisible without actually dividing. 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