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1、年級五年級學(xué)科奧數(shù)版本通用版課程標(biāo)題分?jǐn)?shù)裂項(xiàng)、整數(shù)裂項(xiàng)(二)編稿老師王剛一校林卉二校張琦鋒審核牟翠林分?jǐn)?shù)裂項(xiàng)比整數(shù)裂項(xiàng)稍復(fù)雜,能裂項(xiàng)的分?jǐn)?shù),分母一般是某兩數(shù)的乘積,分子與這兩數(shù)的和或差有關(guān)。當(dāng)算式具有這樣的特征時,可能需要裂成差相抵消,或裂成和再湊對。分?jǐn)?shù)裂項(xiàng)的常見情況:a?bab11????abababba1111?(?)abb?aab2222a?babab????abababba11111例1.計(jì)算:????1?22?33?44?55?6【分析與解】11111????1?22?33?44?55?611111111
2、11?(?)?(?)?(?)?(?)?(?)122334455615?1??66第1頁版權(quán)所有不得復(fù)制例2.【分析與解】本題需要看出所給分母的規(guī)律,它們都是兩個差為2的數(shù)的乘積。1111例3.計(jì)算:???...?1?3?53?5?75?7?997?99?101【分析與解】11101?97111????(?)97?99?101497?99?101497?9999?1011111111833原式??(???????)?41?33?53?55?797?9999?101999934512例4.計(jì)算?????1?2?4?52?
3、3?5?63?4?6?710?11?13?14【分析與解】nn?22(n?2)(n?1)(n?1)(n?2)(n?n?2)(n?n?2)111??(?)222n?n?2n?n?2111??[?]2(n?1)n?2n(n?1)?211175原式??(?)?22?3?212?13?2616第2頁版權(quán)所有不得復(fù)制234599例5.計(jì)算????...?3!4!5!6!100!【分析與解】99100?111???100!100!99!100!11原式=?2100!(答題時間:30分鐘)1.計(jì)算:1?2?3?4?5?6?7?8?
4、...?49?5099989712.計(jì)算:?????1?2?32?3?43?4?599?100?1011223349103.計(jì)算:?????????213243109222224.如果337?a?1?2?3???337,則a=________。5.計(jì)算:1×2×3+2×3×4+3×4×5+…+8×9×10=。第3頁版權(quán)所有不得復(fù)制1.解:1?2?3?4?5?6?7?8?...?49?50?1?(1?1)?3?(3?1)?5?(5?1)???49?(49?1)2222?(1?3?5???49)?(1?3?5???49)
5、?202002.解:9998971???...?1?2?32?3?43?4?599?100?101(101?2)(101?2)(101?3)(101?99)????...?1?2?32?3?43?4?599?100?10110121013101100????????1?2?31?2?32?3?42?3?499?100?10199?100?101101101101111?(????)?(????)1?2?32?3?499?100?1011?32?499?10151?241013.解:122334910?????????
6、213243109122334910?(?)?(?)?(?)???(?)21324310951325181??????2612901111?2?9?(?????)1?22?33?49?109?18104.解:22221?2?3?...?337337?338?675?62?337?195所以a=1955.解:1?2?3?2?3?4?3?4?5???8?9?101??(8?9?10?11?0?1?2?3)4?2?9?10?11?1980第4頁版權(quán)所有不得復(fù)制