简便运算:第一题,13又1/6+15又1/12+17又1/20+19又1/30
来源:学生作业帮 编辑:百度作业网作业帮 分类:数学作业 时间:2024/04/19 20:26:17
简便运算:第一题,13又1/6+15又1/12+17又1/20+19又1/30
第二题,1/1x4+1/4x7+1/7x10+...+1/97x100
第三题,2/3+2/15+2/35+2/63+2/99+2/143
第四题,1又1/10+3又1/40+5又1/88+7又1/154+9又1/238+11又1/340
第二题,1/1x4+1/4x7+1/7x10+...+1/97x100
第三题,2/3+2/15+2/35+2/63+2/99+2/143
第四题,1又1/10+3又1/40+5又1/88+7又1/154+9又1/238+11又1/340
第一题,
13又1/6+15又1/12+17又1/20+19又1/30
= 13+1/6 + 15+1/12 + 17+1/20 + 19+1/30
= (13+15+17+19) + 1/6+1/12 +1/20+1/30
= 64 + 1/(2*3)+1/(3*4) +1/(4*5)+1/(5*6)
= 64 + 1/2-1/3 + 1/3-1/4 + 1/4-1/5 + 1/5-1/6
= 64 + 1/2 + 1/6
= 64 + 2/6
= 64 + 1/3
= 64又1/3
第二题,
1/1x4+1/4x7+1/7x10+...+1/97x100
= 1/3 * { 3/(1x4) + 3/(4x7) + 3/(7x10) + ...+ 3/(97x100) }
= 1/3 * { (1/1-1/4) + (1/4-1/7) + (1/7-1/10) + ...+ (1/97-1/100) }
= 1/3 * (1/1-1/100)
= 33/100
第三题,
2/3+2/15+2/35+2/63+2/99+2/143
= 2/(1x3)+2/(3x5)+2/(5x7)+2/(7x9)+2/(9x11)+2/(11x13)
= 1/1-1/3 + 1/3-1/5 + 1/5-1/7 + 1/7-1/9 + 1/9-1/11 + 1/11-1/13
= 1 - 1/13
= 12/13
第四题,
1又1/10+3又1/40+5又1/88+7又1/154+9又1/238+11又1/340
= 1+1/10+3+1/40+5+1/88+7+1/154+9+1/238+11+1/340
= (1+3+5+7+9+11) + 1/10+1/40+1/88+1/154+1/238+1/340
= 36 + 1/(2*5)+1/(5*8)+1/(8*11)+1/(11*14)+1/(14*17)+1/(17*20)
= 36 + 1/3 * (1/2-1/5+1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20)
= 36 + 1/3 * (1/2 - 1/20)
= 36 + 1/3 * 9/20
= 36 + 3/20
= 36 又3/20
13又1/6+15又1/12+17又1/20+19又1/30
= 13+1/6 + 15+1/12 + 17+1/20 + 19+1/30
= (13+15+17+19) + 1/6+1/12 +1/20+1/30
= 64 + 1/(2*3)+1/(3*4) +1/(4*5)+1/(5*6)
= 64 + 1/2-1/3 + 1/3-1/4 + 1/4-1/5 + 1/5-1/6
= 64 + 1/2 + 1/6
= 64 + 2/6
= 64 + 1/3
= 64又1/3
第二题,
1/1x4+1/4x7+1/7x10+...+1/97x100
= 1/3 * { 3/(1x4) + 3/(4x7) + 3/(7x10) + ...+ 3/(97x100) }
= 1/3 * { (1/1-1/4) + (1/4-1/7) + (1/7-1/10) + ...+ (1/97-1/100) }
= 1/3 * (1/1-1/100)
= 33/100
第三题,
2/3+2/15+2/35+2/63+2/99+2/143
= 2/(1x3)+2/(3x5)+2/(5x7)+2/(7x9)+2/(9x11)+2/(11x13)
= 1/1-1/3 + 1/3-1/5 + 1/5-1/7 + 1/7-1/9 + 1/9-1/11 + 1/11-1/13
= 1 - 1/13
= 12/13
第四题,
1又1/10+3又1/40+5又1/88+7又1/154+9又1/238+11又1/340
= 1+1/10+3+1/40+5+1/88+7+1/154+9+1/238+11+1/340
= (1+3+5+7+9+11) + 1/10+1/40+1/88+1/154+1/238+1/340
= 36 + 1/(2*5)+1/(5*8)+1/(8*11)+1/(11*14)+1/(14*17)+1/(17*20)
= 36 + 1/3 * (1/2-1/5+1/5-1/8+1/8-1/11+1/11-1/14+1/14-1/17+1/17-1/20)
= 36 + 1/3 * (1/2 - 1/20)
= 36 + 1/3 * 9/20
= 36 + 3/20
= 36 又3/20
简便运算:第一题,13又1/6+15又1/12+17又1/20+19又1/30
简算 第一题1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+1
【1又1/10+2又7/20÷(3又1/12-1.125)】×9/23-1/6 简便运算
1+2又6分之1+4又12分之1+8又20分之1+16又30分之1+32又42分之1+64又56分之1简便运算
6又7分之2+(-12又3分之1)-15-(+7又7分之2)-(-12又3分之1)=?简便运算
11又1/2+12又1/6+13又1/12+14又1/20+15又1/30+16又1/42+17又1/56+18又1/7
1+3又1/6+5又1/12+7又1/20+9又1/30+11又1/42+13又1/56+15又1/72+17又1/90
8题分数的计算.1.7又5/6-6又7/12+5又9/20-4又11/30+3又13/42-2又15/56+1又17/7
120×(-5又6分之1+7又8分之5-1又15分之4) (简便运算)
29又7之6 × 30又7分之1简便运算
30又7分之1乘以29又7分之6 简便运算
1又1/2-5/6+7/12-9/20+11/30-13/42+15/56 怎么简便运算