bai4 thực hiện phép tính (tính nhanh nếu có thể )
a) (-1/2) - (-3/5) + (-1/9) + 1/71 - (-2/7) + 4/35 - 7/18
=(-1/9-7/18)+(3/5+4/35)+(-1/2+1/71+2/7)
=(-1/2)+(5/7)+(-1/2+1/71+2/7)
=(-1/2-1/2)+(5/7+2/7)+1/71
=-1+1+1/71
=1/71

b) (3-1/4+2/3) - (5-1/3-6/5) - (6-7/4+3/2)
=(3-5-6)+(-1/4+7/4-3/2)+(2/3+1/3)+6/5
=(-8)+(0)+(1)+6/5
=-7+6/5
=-29/5

c) (5+1/5-2/9) - (2 - 1/23 - 2/3/35 + 5/6) - (8+2/7-1/18)
=(5-2-8)+(1/5+2/(3.5.7)-2/7)+(-2/9+1/18-5/6)+1/23
=(-5)+(21+2-30)/(3.5.7)+(-1)+1/23
=(-6)+(-1/15)+1/23
=-91/15+1/23


d)1/3 - 3/ 4 - (-3/5) + 1/64 - 2/9 -1/36 + 1/15
=(1/3+3/5+1/15)+(-3/4+1/64)+(-1/36-2/9)
=(5+3+1)/15+(-48+1)/64+(-1-8)/36
=3/5+(-47/64)+(-1/4)
=3/5+(-47-16)/64
=3/5-63/64

a) (-1/2) - (-3/5) + (-1/9) + 1/71 - (-2/7) + 4/35 - 7/18
= -1/2 + 3/5 - 1/9 + 1/71 + 2/7 + 4/35 - 7/18
= (-1/2 - 1/9 - 7/18) + (3/5 + 2/7 + 4/35) + 1/71
= (-9/18 - 2/18 - 7/18) + (21/35 + 10/35 + 4/35) + 1/71
= [(-9 - 2 - 7)/18] + [(21+4+10)/35) + 1/71
= (-18/18) + 35/35 + 1/71
= - 1 + 1 + 1/71
= 0 + 1/71
= 1/71
b) (3-1/4+2/3) - (5-1/3-6/5) - (6-7/4+3/2)
= 3 - 1/4 + 2/3 - 5 + 1/3 + 6/5 - 6 + 7/4 - 3/2
= (- 1/4 - 3/2 + 7/4) + (2/3 + 1/3) + 3 - 5 - 6 + 6/5
= (- 1/4 - 6/4 + 7/4) + 1 + 3 - 5 - 6 + 6/5
= (- 7/4 + 7/4) + (1 + 3 - 5 - 6) + 6/5
= 0 - 7 + 6/5
= 6/5 - 7
= 42/35 - 245/35
= (42 - 245)/35
= - 203/35
= - 29/5
Vậy : ...
vô trang mình 5 sao nha

c) (5+1/5-2/9) - [2 - 1/23 - (2/3)/35 + 5/6] - (8+2/7-1/18)
= 5 + 1/5 - 2/9 - 2 + 1/23 + (2/3)/35 - 5/6 - 8 - 2/7 + 1/18)
= 5 + 21/105 - 4/18 - 2 + 1/23 + 2/105 - 15/18 - 8 - 30/105 + 1/18
= (5 - 2 - 8) + (21/105 + 2/105 - 30/105) + (1/18 - 4/18 - 15/18) + 1/23
= - 5 - 1/15 - 1 + 1/23
= - 91/15 + 1/23
≈ - 6
d)1/3 - 3/4 - (-3/5) + 1/64 - 2/9 -1/36 + 1/15
= 1/3 - 3/4 + 3/5 + 1/64 - 2/9 - 1/36 + 1/15
= (- 3/4 - 2/9 - 1/36) + (1/3 + 3/5 + 1/15) + 1/64
= (- 27/36 - 8/36 - 1/36) + (5/15 + 9/15 + 1/15) + 1/64
= - 36/36 + 15/15 + 1/64
= - 1 + 1 + 1/64
= 0 + 0 + 1/64
= 1/64
Vậy : ...
vô trang mình 5 sao nha

e) - 5/7-(-5/67) + 13/30 + 1/2 + ( -1/5/6) + 1/3/14 -(-2/5)
= - 5/7 + 5/67 + 13/30 + 1/2 - 1/5/6 + 1/3/14 + 2/5
= - 5/7 + 5/67 + 13/30 + 1/2 - 11/6 + 17/14 + 2/5
= (- 5/7 + 17/14) + (13/30 + 2/5) + (1/2 - 11/6) + 5/67
= (- 10/14 + 17/14) + (13/30 + 12/30) + (3/6 - 11/6) + 5/67
= 7/14 + 25/30 - 8/6 + 5/67
= 1/2 + 5/6 - 4/3 + 5/67
= 6/12 + 10/12 - 16/12 + 5/67
= 0 + 5/67
= 5/67
vô trang mình 5 sao nha

cảm ơn tất cả các bạn nha

 (-1/2) - (-3/5) + (-1/9) + 1/71 - (-2/7) + 4/35 - 7/18