速算巧算的题40道.急

4个回答

  • 1.计算 4.75-9.64+8.25-1.36=_____.

    2.计算 3.17-2.74+4.7+5.29-0.26+6.3=_____.

    3.计算 (5.25+0.125+5.75) 8=_____.

    4.计算 34.5 8.23-34.5+2.77 34.5=_____.

    5.计算 6.25 0.16+264 0.0625+5.2 6.25+0.625 20=_____.

    6.计算 0.035 935+0.035+3 0.035+0.07 61 0.5=_____.

    7.计算 19.98 37-199.8 1.9+1998 0.82=_____.

    8.计算 13.5 9.9+6.5 10.1=_____.

    9.计算 0.125 0.25 0.5 64=_____.

    10.计算 11.8 43-860 0.09=_____.

    11.计算 32.14+64.28 0.5378 0.25+0.5378 64.28 0.75-8 64.28 0.125 0.5378.

    12.计算 0.888 125 73+999 3.

    13.计算 1998+199.8+19.98+1.998.

    14.下面有两个小数:

    a=0.00…0125 b=0.00…08

    1996个0 2000个0

    试求a+b,a-b,a b,a b.

    1+0.99-0.98-0.97+0.96+0.95-0.94-0.93+…+0.04+0.03-0.02-0.01

    习题一

    一、直接写出计算结果:

    ① 1000-547

    ② 100000-85426

    ③ 11111111110000000000-1111111111

    ④ 78053000000-78053

    二、用简便方法求和:

    ①536+(541+464)+459

    ② 588+264+148

    ③ 8996+3458+7546

    ④567+558+562+555+563

    三、用简便方法求差:

    ① 1870-280-520

    ② 4995-(995-480)

    ③ 4250-294+94

    ④ 1272-995

    四、用简便方法计算下列各题:

    ① 478-128+122-72

    ② 464-545+99+345

    ③ 537-(543-163)-57

    ④ 947+(372-447)-572

    五、巧算下列各题:

    ① 996+599-402

    ② 7443+2485+567+245

    ③ 2000-1347-253+1593

    ④3675-(11+13+15+17+19)

    一、直接写出计算结果:

    ① 1000-547=453

    ② 100000-85426=14574

    ③ 11111111110000000000-1111111111

    =11111111108888888889

    ④ 78053000000-78053=78052921947

    此题主要是练习直接写出“补数”的方法:从最高位写起,其各位数字用“凑九”而得,最后个位凑10而得.

    二、用简便方法求和:

    ① 536+(541+464)+459

    =(536+464)+(541+459)

    =2000

    ② 588+264+148

    =588+(12+252)+148

    =(588+12)+(252+148)

    =600+400

    =1000

    ③ 8996+3458+7546

    =(8996+4)+(3454+7546)

    =9000+11000(把 3458分成 4和=9000+11000 3454)

    =20000

    ④ 567+558+562+555+563

    =560×5+(7-2+2-5+3)(以560为基准数)

    =2800+5=2805

    三、用简便方法求差:

    ① 1870-280-520

    =1870-(280+520)

    =1870-800

    =1070

    ②4995-(995-480)

    =4995-995+480

    =4000+480=4480

    ③ 4250-294+94

    =4250-(294-94)

    =4250-200=4050

    ④ 1272-995

    =1272-1000+5

    =277

    四、用简便方法计算加减混合运算:

    ① 478-128+122-72

    =(478+122)-(128+72)

    =600-200

    =400

    ② 464-545+99+345

    =464-(545-345)+100-1

    =464-200+100-1

    =363

    ③537-(543-163)-57

    =537-543+163-57

    =(537+163)-(543+57)

    =700-600

    =100

    ④ 947+(372-447)-572

    =947+372-447-572

    =(947-447)-(572-372)

    =500-200

    =300

    五、巧算下列各题:

    ①996+599-402=1193

    ②7443+2485+567+245=10740

    ③2000-1347-253+1593=1993

    ④3675-(11+13+15+17+19)=3600