, since all of the valid 4-digit number will always be greater than 
. [/et_pb_tab][et_pb_tab title="HINT 2" _builder_version="4.1"]The best way to solve this problem is by using casework. Now think what are the cases? [/et_pb_tab][et_pb_tab title="HINT 3" _builder_version="4.1"]It has two cases , as there can be only two leading digits, namely 
or 
.[/et_pb_tab][et_pb_tab title="HINT 4" _builder_version="4.1"]We know that number of ways of arranging ‘n’ items, out of which ‘p’ are alike, ‘q’ are alike and ‘r’ are alike given that p + q + r = nNumber of ways of distributing ‘n’ distinct items, in groups of size ‘p’, ‘q’ and ‘r’ given that p + q + r = n
.. Now try to calculate the the two cases .[/et_pb_tab][et_pb_tab title="HINT 5" _builder_version="4.1"]CASE 1:As 2012 consits of two 2's , one 1, 0 so if we set 1 as the leading digit then we have two twos and one 0 such numbers then we have 
such numbers. [/et_pb_tab][et_pb_tab title="HINT 6" _builder_version="4.1"]When the leading digit is then we have one 2, one 1 and one 0 then we can arrange them in 
ways and as such we have 6 such numbers.[/et_pb_tab][et_pb_tab title="HINT 7" _builder_version="4.1"]By addition principle we find that there are 9 such numbers.[/et_pb_tab][/et_pb_tabs][et_pb_text _builder_version="3.27.4" text_font="Raleway|300|||||||" text_text_color="#ffffff" header_font="Raleway|300|||||||" header_text_color="#e2e2e2" background_color="#0c71c3" custom_margin="50px||50px" custom_padding="20px|20px|20px|20px" border_radii="on|5px|5px|5px|5px" box_shadow_style="preset3"]
In 2026, the following Cheenta students have been successful for Indian Statistical Institute's M.Stat Entrance. They ranked within the first 50 in the entire country in these entrances. I.S.I. M.Stat Entrance
In 2026, the following Cheenta students have been successful for Indian Statistical Institute's B.Stat Entrance and Chennai Mathematical Institute's B.Sc. Math Entrance. They ranked within the first 200 in the entire country in these entrances. Most of these students attended the problem solving workshops regularly, which happen 5 days every week. CMI B.Sc. Math Entrance […]
In 2025, 8 students from Cheenta Academy cracked the prestigious Regional Math Olympiad. In this post, we will share some of their success stories and learning strategies. The Regional Mathematics Olympiad (RMO) and the Indian National Mathematics Olympiad (INMO) are two most important mathematics contests in India.These two contests are for the students who are […]
Cheenta Academy proudly celebrates the success of 27 current and former students who qualified for the Indian Olympiad Qualifier in Mathematics (IOQM) 2025, advancing to the next stage — RMO. This accomplishment highlights their perseverance and Cheenta’s ongoing mission to nurture mathematical excellence and research-oriented learning.
