Page 13 - Bangladesh_classwiz_BOOK2018_rev_Neat

K¨vjKz‡jU‡ii gva¨‡g c~Y© msL¨v QvovI fMœvskhy³ NvZwewkó msL¨v¸‡jvi gvb mivmwi †ei Kiv hvq| GRb¨ cÖ_‡g
wfwË cÖ‡ek Kwi‡q ^ Kx Gi ci a Kx e¨envi Ki‡Z nq|

wØZxq w¯Œ‡bi Rb¨ $ Lye mveavbZvi mv‡_ e¨envi Ki‡Z n‡e|

wØZxq w¯Œ‡b jÿYxq †h, GKB wfwËhy³ msL¨v¸‡jv ¸Y‡bi mgq NvZ¸‡jv †hvM n‡q‡Q|
1 2 1 2 3
+
A_©vr, 7 5 × 7 5 = 7 5 5 = 7 5 = ⋯ GLv‡b ‡`Lv hv‡”Q †h, msL¨v `ywUi wfwË GK wKš‘ NvZ¸‡jv wfbœ| G‡ÿ‡Î
2
2
2
2
NvZ¸‡jv †hvM Kiv n‡q‡Q| Z…Zxq w¯Œ‡b †`Lv hv‡”Q †h, 5 × 7 = (5 × 7) = 35 = 1225. GLv‡b
†`Lv hv‡”Q †h, msL¨vwU `ywUi wfwË wfbœ wKš‘ NvZ GKB| G‡ÿ‡Î wfw˸‡jv‡K ¸Y K‡i Zvi Dci NvZ †`qv n‡q‡Q|

1.6 msL¨vi Drcv`K

‡Kv‡bv GKwU c~Y© msL¨v‡K ‡hmKj c~Y© msL¨v Øviv fvM Kiv hvq, Zv‡`i‡K cÖ_‡gv³ c~Y©©msL¨vi Drcv`K e‡j|

D`vniY¯^iƒc, 12 Gi Drcv`Kmg~n n‡jv 1, 2, 3, 4, 6 Ges 12| me c~Y© msL¨viB Kgc‡ÿ `yBwU Drcv`K _v‡K|
†h mKj c~Y© msL¨vi 2 Gi AwaK Drcv`K _v‡K Zv‡`i †hŠwMK msL¨v ejv nq| Ab¨ w`‡K hv‡`i gvÎ `yBwU Drcv`K
_v‡K; GKwU n‡jv msL¨vwU wb‡R Ges Ab¨wU 1, GB ai‡bi msL¨v‡K †gŠwjK msL¨v e‡j| K¨vjKz‡jU‡i GKwU we‡kl
wb‡`©kbv Av‡Q hv ‡Kv‡bv msL¨v‡K Zvi †gŠwjK Drcv`‡Ki ¸wYZK iƒ‡c Dc¯’vcb K‡i| GwU n‡jv FACT| ‡Kv‡bv
msL¨vi Drcv`K †ei Kivi Rb¨ cÖ_‡g msL¨vwU K¨vjKz‡jU‡i cÖ‡ek Kwi‡q = Pvc‡Z n‡e| Gici qx

evUb Pvc‡j wb‡Pi g‡Zv K‡i msL¨vwUi Drcv`K cvIqv hv‡e| FACT (qx) e¨envi K‡i Avgiv Lye mn‡RB
†gŠwjK I †hŠwMK msL¨vi cv_©K¨ Ki‡Z cvwi|

2
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Dc‡ii w¯Œ‡b †`Lv hv‡”Q †h, 3 Gi †gŠwjK Drcv`K ïay 3 wKš‘ 12 Gi Drcv`K¸‡jv 2 , 3; 2 = 4, 2 ×
3 = 6, 4 × 3 = 12 hv †_‡K ‡evSv hvq †h, 3 GKwU †gŠwjK msL¨v| wKš‘ 12 GKwU †hŠwMK msL¨v| ‡h‡nZz 1
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†gŠwjK msL¨v bq, ZvB GwU †gŠwjK Drcv`‡Ki AšÍf‚©³ bq| †h‡Kv‡bv abvZ¥K c~Y msL¨v‡K GKwU Abb¨ †gŠwjK
msL¨vi ¸wYZ‡Ki †mU Øviv cÖKvk Kiv hvq|

cÖ_g K‡qKwU †gŠwjK msL¨v n‡jv 2, 3, 5, 7, 11, 13, … … … …

‡hgb cÖ_g w¯Œ‡b `yBwU c~Y msL¨vi ¸Yb cÖwµqv †`Lv‡bv n‡q‡Q hvi dj 14040| djvdj cvIqvi ci qx
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†P‡c FACT wb‡`k©bv w`‡j msL¨vwUi †gŠwjK Drcv`K¸‡jv wØZxq w¯Œ‡bi g‡Zv †`Lv hv‡e|

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