Mistakes in math textbook

Numbers reading in other languages are comparatively easy. Once you know the numbers up to ten or twenty then you can read the other numbers easily. For example, Arabic language: wahid (1), ithnan (2), salasa (3), arba’a (4), khamsa (5), sitta (6), sab’a (7), thamaniya (8), tis’a (9), ‘ashra (10). Wahida ‘ashar (11), ithna ‘ashar (12), salasa ‘ashar (13), arba’a ‘ashar (14), khamsa ‘ashar (15), sitta ‘ashar (16), sab’a ‘ashar (17), thamaniya ‘ashar (18), tis’a ‘ashar (19), ‘ishrun (20), wahed wa-’ishrun (21), ithnane wa-’ishrun(21) and so on.
I can give you an example of Japanese language, French language, and some other languages and we know the numbers in the English Language as well.
But in Bangla language, we do not find any pattern like these. Students have to memorize all the numbers up to hundred and after that one can get the pattern.
Students are struggling in many cases like 13, 23, 33, 43, 53 (but different in তিপ্পান্ন), 63, 73 (again different in তিয়াত্তর) and the next two are also different. Actually, students have to memorize all the numbers carefully.
Nevertheless, a few people who are involved in NCTB provide students wrong spellings of 29, 39, 49, 59, 69, 79, 89 and put them into extra trouble. I talked to a few of them physically in a workshop and over telephone as well a long time ago and showed them the latest Bangla Academy dictionary edited by Jamil Choudhury and where all the spellings were written in (উন instead of ঊন) ie. উনত্রিশ, উনচল্লিশ, উনপঞ্চাশ, উনষাট, উনসত্তর, উনআশি, উননব্বই and which are correct. But the NCTB still following the same, wrong spelling (ঊনত্রিশ, ঊনচল্লিশ, ঊনপঞ্চাশ, ঊনষাট, ঊনসত্তর, ঊনআশি, ঊননব্বই) but only উনিশ (19) is found correct in the textbooks. So, students have to memorize 19 for উ and the others for ঊ. The others for ঊ is wrong. There are a few other mistakes in the textbooks as well.
So, I would like to request to the concerned authorities to use the correct spelling and correct all the mistakes from next year and upload all the textbooks on the internet along with English version at the beginning of the year.