2×5、4×25、8×125を利用する掛け算の応用 No.3(暗算の練習用の計算問題)
2×5、4×25、8×125を利用して計算を簡単にする掛け算です。
・×5 → 2×5の利用 → ÷2×10
・×25 → 4×5の利用 → ÷4×100
・×125 → 8×125の利用 → ÷8×1000
ただ、このページでは、×5、×25、×125が見つけにくくなっています。その場合は以下と捉えておくといいでしょう。
・25の倍数は、「25、50、75、100」「125、150、175、200」「225、250…」と4セット
・125の倍数は「125、250、375、500、625、750、875、1000」「1125、1250…」と8セット
なお、暗算の具体的な方法は、中学入試計算名人免許皆伝、インド式 超速★計算術、子供のインド式「かんたん」計算ドリルなどの書籍をご覧になってください(インド式はすべてを取り入れず、2桁の掛け算のみ取り入れるなどとするといいでしょう)。
※印刷してご利用ください。紙を半分あたりで折ると解答を隠せます。
※商用利用も可能です(連絡不要です)。
※プログラムで作成しています。間違いがあればお知らせしていだければ幸いです。
(1)376×375=
(2)284×725=
(3)116×925=
(4)85×146=
(5)725×244=
(6)212×575=
(7)118×415=
(8)325×172=
(9)296×875=
(10)305×106=
(11)295×166=
(12)632×375=
(13)325×332=
(14)575×76=
(15)1125×536=
(16)158×215=
(17)325×244=
(18)475×172=
(19)104×1125=
(20)152×1125=
(21)82×355=
(22)875×568=
(23)925×148=
(24)236×725=
(25)134×95=
(26)584×1125=
(27)875×296=
(28)425×356=
(29)375×584=
(30)26×235=
(31)415×58=
(32)475×244=
(33)284×925=
(34)375×776=
(35)95×62=
(36)575×316=
(37)375×776=
(38)725×212=
(39)1125×472=
(40)235×146=
(41)725×68=
(42)875×488=
(43)172×925=
(44)575×188=
(45)104×875=
(46)375×136=
(47)166×265=
(48)145×106=
(49)925×68=
(50)712×375=
(51)74×215=
(52)344×875=
(53)664×1125=
(54)164×325=
(55)775×52=
(56)116×325=
(57)316×475=
(58)775×172=
(59)632×1125=
(60)62×395=
(61)775×236=
(62)725×388=
(63)52×725=
(64)776×375=
(65)356×575=
(66)475×148=
(67)178×235=
(68)355×74=
(69)124×425=
(70)316×775=
(71)68×775=
(72)118×95=
(73)475×116=
(74)472×875=
(75)236×325=
(76)116×775=
(77)284×325=
(78)65×46=
(79)104×1125=
(80)58×365=
(81)415×94=
(82)925×268=
(83)292×925=
(84)248×1125=
(85)536×875=
(86)145×178=
(87)194×205=
(88)166×205=
(89)194×415=
(90)115×158=
(91)536×375=
(92)424×375=
(93)664×875=
(94)106×215=
(95)145×34=
(96)134×305=
(97)475×124=
(98)488×875=
(99)235×118=
(100)205×94=
(101)575×356=
(102)445×146=
(103)875×536=
(104)115×62=
(105)164×725=
(106)158×205=
(107)925×116=
(108)295×38=
(109)236×925=
(110)62×485=
(111)725×164=
(112)875×376=
(113)1125×488=
(114)664×375=
(115)68×575=
(116)295×94=
(117)712×375=
(118)415×58=
(119)925×388=
(120)775×164=
(121)344×1125=
(122)34×85=
(123)575×388=
(124)344×1125=
(125)325×332=
(126)632×375=
(127)445×118=
(128)425×92=
(129)148×775=
(130)146×65=
(131)875×776=
(132)212×775=
(133)445×26=
(134)335×122=
(135)875×296=
(136)575×172=
(137)76×475=
(138)925×188=
(139)325×116=
(140)94×265=
(141)875×632=
(142)172×925=
(143)925×68=
(144)375×488=
(145)178×235=
(146)74×235=
(147)85×134=
(148)632×1125=
(149)164×325=
(150)284×475=
(2)284×725=
(3)116×925=
(4)85×146=
(5)725×244=
(6)212×575=
(7)118×415=
(8)325×172=
(9)296×875=
(10)305×106=
(11)295×166=
(12)632×375=
(13)325×332=
(14)575×76=
(15)1125×536=
(16)158×215=
(17)325×244=
(18)475×172=
(19)104×1125=
(20)152×1125=
(21)82×355=
(22)875×568=
(23)925×148=
(24)236×725=
(25)134×95=
(26)584×1125=
(27)875×296=
(28)425×356=
(29)375×584=
(30)26×235=
(31)415×58=
(32)475×244=
(33)284×925=
(34)375×776=
(35)95×62=
(36)575×316=
(37)375×776=
(38)725×212=
(39)1125×472=
(40)235×146=
(41)725×68=
(42)875×488=
(43)172×925=
(44)575×188=
(45)104×875=
(46)375×136=
(47)166×265=
(48)145×106=
(49)925×68=
(50)712×375=
(51)74×215=
(52)344×875=
(53)664×1125=
(54)164×325=
(55)775×52=
(56)116×325=
(57)316×475=
(58)775×172=
(59)632×1125=
(60)62×395=
(61)775×236=
(62)725×388=
(63)52×725=
(64)776×375=
(65)356×575=
(66)475×148=
(67)178×235=
(68)355×74=
(69)124×425=
(70)316×775=
(71)68×775=
(72)118×95=
(73)475×116=
(74)472×875=
(75)236×325=
(76)116×775=
(77)284×325=
(78)65×46=
(79)104×1125=
(80)58×365=
(81)415×94=
(82)925×268=
(83)292×925=
(84)248×1125=
(85)536×875=
(86)145×178=
(87)194×205=
(88)166×205=
(89)194×415=
(90)115×158=
(91)536×375=
(92)424×375=
(93)664×875=
(94)106×215=
(95)145×34=
(96)134×305=
(97)475×124=
(98)488×875=
(99)235×118=
(100)205×94=
(101)575×356=
(102)445×146=
(103)875×536=
(104)115×62=
(105)164×725=
(106)158×205=
(107)925×116=
(108)295×38=
(109)236×925=
(110)62×485=
(111)725×164=
(112)875×376=
(113)1125×488=
(114)664×375=
(115)68×575=
(116)295×94=
(117)712×375=
(118)415×58=
(119)925×388=
(120)775×164=
(121)344×1125=
(122)34×85=
(123)575×388=
(124)344×1125=
(125)325×332=
(126)632×375=
(127)445×118=
(128)425×92=
(129)148×775=
(130)146×65=
(131)875×776=
(132)212×775=
(133)445×26=
(134)335×122=
(135)875×296=
(136)575×172=
(137)76×475=
(138)925×188=
(139)325×116=
(140)94×265=
(141)875×632=
(142)172×925=
(143)925×68=
(144)375×488=
(145)178×235=
(146)74×235=
(147)85×134=
(148)632×1125=
(149)164×325=
(150)284×475=
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