二年级下奥数100题及答案.doc

1. 72444172721+4+4=884=3232.2. (1)(2)(3)?(2)(1)(3)(3)3. 106254. 3005612856+128=184()1845. 6. 23323-3=2020/3+1=555*3+3=187. 1248791013141579101314151248.7=1+2+4 9=1+810=2+813=1+4+814=2+4+815=1+2+4+8.8. ( )( ( )()()()9. 34889989898998988998989988799997999979999710. 1028828810-1 28810-1=32 3210=320 3203211. 10 5 4 12. 551.13. 4 2 4 8 2 1 1 8 1214. 521812(1) 18 12 52-12=40()(52-12)+18=58()(2)18 12 125218-126()52+(18-12)=58()(3) 18 121852+18=70()12(52+18)-12=58()15. 424821181216. 661505150666666617. .65.?1523.18. 32619. 110010073159134126101442371143481240473734=181.7320. 4311221. 12+-7 2 4 6 9 5 1 = 724218?12+-72 4 6 9 5 1=72 + 4 + 6 C 9 + 5 C 1 = 724218?(184)2+1=8()(18+4)82=88()22. 3623. 12468 2147 3302520 1 21012 2 31013 3 5151024. 2016102016=42010=10 204 10=625. 6334626. +=15+=12+=18+= 151218=5=4=65+4+6=15 1527. 19911111213141516171819110;11011121314151617181910;10+10=20.28. 504976 76.5049 76-50=26 49-26=23 50-23=2729. 54610.?45-4=161+6=71010-7=330. 61187( )6118767421226112331. 20293821?12032. 15 135791113, 15 833. 65825858=40626-2=4404404=101034. 18110112( )( )1811011211435. 3023?302=1515-3-1=11()36. 20.101.20-10-1=9 10009=9000 99000.37. 11531118150( )1=31503=45038. 1+3=10 8=16 1=( ) 1=( )()1=21+6=101=41=21=239. ,312.40. 05605696450565960659095750656060565069509.590.950.905.44+7+4=1541. 2?42. 14317( )1431176643. 25 251232343454569,14144. 14214214/2=7()12=-1=6()45. 1+=2=3+=-12222 =2 =0211=11 1 300=0-0 =046. 32.5454554514+132.52+54+1=65+55=705=14144-5=56-5=51511447. 1 12 72248. 101410+14=24() 24/3=8() 10-8=2() 14-8=6()49. 195198193. +=195 1 +=198 2 +=193 3 2+=586 +=293 4 4-1 =293-195=98 4-2 =293-198=95 4-3 =293-193=100 9895100.50. 1006010060100-60=4080100-80=2051. 4410_310303152. 4 ? L 53. ? + = 9 + + + + = 25 = ( ) ; = ( ) + = 9+=25+99+=259+9+=25=7+=9=7=254. *? (1)+5=13-6; (2)28-=15+7; (3)3=54; (4)3=87; (5)56*=7(1)=13-6-5=2; (2)=28-(15+7)=6; (3)=543=18; (4)=873=261; (5)*=567=855. 1?1056. +=3054+5+6+7+8=3057. .58. 120100120220120359. 5555555553025252553035303056156651 5525 25530 3056 651 160. 6461. ?144101441 2 3 4 6 8 9 12144 72 48 36 24 18 16 121081862. 582020120-1=19520195=9513520935.63. 10010033133333=99100-99=1333+3=3610030330=9010310=3030+30=6025325=75100-75=25325=7525+75=100257564. 100 199119=9 1099902290=180100131009+180+3=192 65. 32x4=8 3866. 3583215( )21525026367. 12.3.4568. 4223AB2ACB2BAC269. 144101441081870. 243610 () 24 ()71. 553421512345152433425135 ()72. 1215653222100%53+2=5622100%2+2+2=6 73. AB520AA,5?AB205=100()74. 368-199?=368-200+1 =168+1 =16975. 195198193.+=195 1+=198 2+=193 32+=586+=293 44-1=293-195=984-2=293-198=954-3=293-193=1009895100.76. ?41044030;44051030.30+30=60 60=1 30.1.77. 14916 1+4+9+16=30()78. 78.1231+12*12/2=78 1279. M*N=(M+N)2(2008*2010)*2009=_ 2008*2010=2008+20102=2009 2009*2009=2009+20092=200980. 507,50=7x7+1,1150.81. 82. ?123. 1+2+3=6 123=6 1+2+3=1238