三年级奥数：速算与巧算习题及答案（B）.doc

第一章 速算与巧算(B) 年级 班 姓名 得分 1.987-178-222-390 2.325+46-125+54 3.567+558+562+555+563 4.67(12+67(35+67(52+67 5.2997(729((81(81) 6.456(2(125(25(5(4(8 7.25(32(125 8.(702-213-414)(3 9.999(99(9 10.21(9+22(9+23(9+24(9 11.1200(25 12.1989199013.9999(1111+3333(6667 14.100+99-98+97-96+…+3-2+1 ———————————————答 案—————————————————————— 1. 197 原式=987-(178+222)-390 =987-400-400+10 =197 2. 300 原式=325-125+46+54 =(325-125)+(46+54) =200+100 =300 3. 2805 原式=560(5+(7-2+2-5+3) =2800+5 =2805 4. 6700 原式=67((12+35+52+1) =67(100 =6700 5. 333 原式=2997(729(81(81 =(2997(81)((728(81) =37(9 =333 6. 456000000 原式=456((2(5)((25(4)((125(8) =456(10(100(1000 =456000000 7. 100000 原式=(25(4)((8(125) =100(1000 =100000 8. 25 原式=702(3-213(3-414(3 =234-71-138 =25 9. 890109 原式=(1000-1)(99(9 =(99000-99)(9 =98901((10-1) =989010-98901 =890109 10. 10 原式=(21+22+23+24)(9 =(21+24)(4(2(9 =45(4(2(9 =45((4(2)(9 =45(2(9 =90(9 =10 11. 48 1200(25=(1200(4)((25(4) =4800(100 =48 12. 0 原式=1989(1990(10001-1990(1989(10001 =0 13. 原式=3333(3(1111+3333(6667 =3333(3333+3333(6667 =3333((3333+6667) =3333(10000 14. 150 原式=100+(99-98)+(97-96)+…(3-2)+1 =100+1+1+…+1+1+1 49个1 =100+49+1 =150 小学奥数讲练