7道简便计算、一道10分.谢谢大家了。( / ←此为分数线)
1.1×2+2×3+3×4+……10×11
2.9999×2222+3333×3334
3.0.5×236×59/119
4.238÷238又238/239 (带分数)
5.125又1/20(带分数)÷41
6.6209/10013×10693/22869÷3337/10602
7.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
1.=2×(1+3)+4×(3+5)+6×(5+7)+8×(7+9)+10×(9+11)
=2×2×2+2×4×4+2×6×6+2×8×8+2×10×10
=2×(4+16+36+64+100)
=2×220=440
2.=3333×6666+3333×3334
=3333×(6666+3334)
=33330000
3.=0.5×2×118×59÷119
=58.50420168......【请检查题目】
4.将式子倒过来:238又238/239÷238=1又1/239=240/239
所以原式=239/240
5.=(123+2又1/20)÷41
=123÷41+41/20÷41
=3+1/20=3又1/20(或61/20)
6.=0.921173486【似乎没有简便算法,检查题目是否正确】
7.=(1/2+1/4)+(1/7+1/14+1/28)-1/3-1/5-1/15-1/30
=3/4+1/4-(10+6+2+1)/30
=11/30
=2×2×2+2×4×4+2×6×6+2×8×8+2×10×10
=2×(4+16+36+64+100)
=2×220=440
2.=3333×6666+3333×3334
=3333×(6666+3334)
=33330000
3.=0.5×2×118×59÷119
=58.50420168......【请检查题目】
4.将式子倒过来:238又238/239÷238=1又1/239=240/239
所以原式=239/240
5.=(123+2又1/20)÷41
=123÷41+41/20÷41
=3+1/20=3又1/20(或61/20)
6.=0.921173486【似乎没有简便算法,检查题目是否正确】
7.=(1/2+1/4)+(1/7+1/14+1/28)-1/3-1/5-1/15-1/30
=3/4+1/4-(10+6+2+1)/30
=11/30
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第1个回答 2010-07-14
1.1×2+2×3+3×4+……10×11
=2×4+3×4+……10×11
=398
2.9999×2222+3333×3334
=9999*2222+3333*3333+3333
=3333(6666+3333+1)
=33330000
3.0.5×236×59/119
=118*59/17*7
4.238÷238又238/239 (带分数)
=238*239/240*238=239/240
5.125又1/20(带分数)÷41
=2501/20*(1/41)
=61/20
6.6209/10013×10693/22869÷3337/10602
=6209/10013×10693/22869×10602/3337
=(6209*10693*1178)/(10013*2541*3337)
7.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
=(1/2+1/4+1/7+1/14+1/28)-(1/3+1/5+1/10+1/15+1/30)
=(14+7+4+2+1)/28-(10+6+3+2+1)/30
=1-11/15=4/15
=2×4+3×4+……10×11
=398
2.9999×2222+3333×3334
=9999*2222+3333*3333+3333
=3333(6666+3333+1)
=33330000
3.0.5×236×59/119
=118*59/17*7
4.238÷238又238/239 (带分数)
=238*239/240*238=239/240
5.125又1/20(带分数)÷41
=2501/20*(1/41)
=61/20
6.6209/10013×10693/22869÷3337/10602
=6209/10013×10693/22869×10602/3337
=(6209*10693*1178)/(10013*2541*3337)
7.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)
=(1/2+1/4+1/7+1/14+1/28)-(1/3+1/5+1/10+1/15+1/30)
=(14+7+4+2+1)/28-(10+6+3+2+1)/30
=1-11/15=4/15
第2个回答 2010-07-14
1.=2×(1+3)+4×(3+5)+6×(5+7)+8×(7+9)+10×(9+11)
=2×2×2+2×4×4+2×6×6+2×8×8+2×10×10
=2×(4+16+36+64+100)
=2×220=440
2.=3333×6666+3333×3334
=3333×(6666+3334)
=33330000
3.=0.5×2×118×59÷119
=58.50420168......【请检查题目】
4.将式子倒过来:238又238/239÷238=1又1/239=240/239
所以原式=239/240
5.=(123+2又1/20)÷41
=123÷41+41/20÷41
=3+1/20=3又1/20(或61/20)
6.=0.921173486【似乎没有简便算法,检查题目是否正确】
7.=(1/2+1/4)+(1/7+1/14+1/28)-1/3-1/5-1/15-1/30
=3/4+1/4-(10+6+2+1)/30
=11/30
很高兴为你解答
谢谢
=2×2×2+2×4×4+2×6×6+2×8×8+2×10×10
=2×(4+16+36+64+100)
=2×220=440
2.=3333×6666+3333×3334
=3333×(6666+3334)
=33330000
3.=0.5×2×118×59÷119
=58.50420168......【请检查题目】
4.将式子倒过来:238又238/239÷238=1又1/239=240/239
所以原式=239/240
5.=(123+2又1/20)÷41
=123÷41+41/20÷41
=3+1/20=3又1/20(或61/20)
6.=0.921173486【似乎没有简便算法,检查题目是否正确】
7.=(1/2+1/4)+(1/7+1/14+1/28)-1/3-1/5-1/15-1/30
=3/4+1/4-(10+6+2+1)/30
=11/30
很高兴为你解答
谢谢
第3个回答 2010-07-14
1.假设A=1×2+2×3+3×4+........+10×11,
3*A=1×2*3+2×3*3+3×4*3+........+10×11*3
=1×2*3+2×3*(4-1)+3×4*(5-2+........+10×11*(12-9)
=1*2*3+2*3*4-1*2*3+3*4*5-2*3*4+……+10*11*12-9*10*11
=10*11*12=1320
所以A= 440(小学学高阶等差数列,,,汗)
2.原式=3333*3*2222+3333*3334
=3333*(3*2222+3334)
=3333*(6666+3334)
=3333*10000=33330000
3. 原式=1/2×118×2×59/119
=1/2×(118×118)/119
=1/2×(119×119-119-118)/119
=1/2×(119-1-1+1/119)
=1/2×117+1/238=1/234 +1/238
4.原式=238÷((238*239+239-1)/239)
=238 ÷(239*239-1)/239
=238÷239 -238*239= 1-1/239 -(240-2)(240-1)
5.原式=125又1/20(带分数)÷41
=(125*20+1)/20÷41
=61*41/20÷41
=61/20=3.05
6.这个真不会
7.原式=1/2-1/3+1/4-1/5+1/7-1/10+1/14-1/15+1/28-1/30
=(1/2+1/4)-(1/3+1/15+1/30)-(1/5+1/10)+(1/7+1/14+1/28)
=1-1/4 -1/2+1/15-3/10+1/4=1/2+1/15-3/10=(15+2-9)/30=4/15
3*A=1×2*3+2×3*3+3×4*3+........+10×11*3
=1×2*3+2×3*(4-1)+3×4*(5-2+........+10×11*(12-9)
=1*2*3+2*3*4-1*2*3+3*4*5-2*3*4+……+10*11*12-9*10*11
=10*11*12=1320
所以A= 440(小学学高阶等差数列,,,汗)
2.原式=3333*3*2222+3333*3334
=3333*(3*2222+3334)
=3333*(6666+3334)
=3333*10000=33330000
3. 原式=1/2×118×2×59/119
=1/2×(118×118)/119
=1/2×(119×119-119-118)/119
=1/2×(119-1-1+1/119)
=1/2×117+1/238=1/234 +1/238
4.原式=238÷((238*239+239-1)/239)
=238 ÷(239*239-1)/239
=238÷239 -238*239= 1-1/239 -(240-2)(240-1)
5.原式=125又1/20(带分数)÷41
=(125*20+1)/20÷41
=61*41/20÷41
=61/20=3.05
6.这个真不会
7.原式=1/2-1/3+1/4-1/5+1/7-1/10+1/14-1/15+1/28-1/30
=(1/2+1/4)-(1/3+1/15+1/30)-(1/5+1/10)+(1/7+1/14+1/28)
=1-1/4 -1/2+1/15-3/10+1/4=1/2+1/15-3/10=(15+2-9)/30=4/15
第4个回答 2010-07-14
1.1×2+2×3+3×4+……10×11=440
2.9999×2222+3333×3334=33330000
3.0.5×236×59/119=6962/119
4.238÷238又238/239 (带分数)=238/239
5.125又1/20(带分数)÷41=25/164
6.6209/10013×10693/22869÷3337/10602=8.195318367*10的-9次方(题目可能有错)
7.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)=4/15
请你核对题目是否出错
2.9999×2222+3333×3334=33330000
3.0.5×236×59/119=6962/119
4.238÷238又238/239 (带分数)=238/239
5.125又1/20(带分数)÷41=25/164
6.6209/10013×10693/22869÷3337/10602=8.195318367*10的-9次方(题目可能有错)
7.(1/2-1/3)+(1/4-1/5)+(1/7-1/10)+(1/14-1/15)+(1/28-1/30)=4/15
请你核对题目是否出错
第5个回答 2010-07-15
4. 238+238又238/239
=238*2-1/239
=476-1/239
=175又238/239
5.125又1/20+41
=166又1/20
=238*2-1/239
=476-1/239
=175又238/239
5.125又1/20+41
=166又1/20