1. Tính
a) -1/8 + -5/3
b) -6/35 . -49/54
c) -4/5 : 3/4
2. Tính nhanh
a) 31/17 + -5/13 + -8/13 – 14/17
b) -5/7 . 2/11 + -5/7 . 9/11 + 5/7
1. Tính
a) -1/8 + -5/3
b) -6/35 . -49/54
c) -4/5 : 3/4
2. Tính nhanh
a) 31/17 + -5/13 + -8/13 – 14/17
b) -5/7 . 2/11 + -5/7 . 9/11 + 5/7
Đáp án + Giải thích các bước giải:
Bài 1:
`a) -1/8 + -5/3 = -43/24`
`b) -6/35 . -49/54 = 7/45`
`c) -4/5 : 3/4 = -16/15`
Bài 2:
`a) 31/17 + -5/13 + -8/13 – 14/17`
`= (31/17 -14/17) + (-5/13 + -8/13)`
`= 1 + (-1)`
`= 0`
`b) -5/7 . 2/11 + -5/7 . 9/11 + 5/7`
`= -5/7 . ( 2/11 + 9/11) + 5/7`
`= -5/7 . 1 + 5/7`
`= -5/7 + 5/7`
`= 0`
`1.`
`a) -1/8+-5/3=-43/24`
`b) -6/35 × -49/54=7/45`
`c) -4/5:3/4=-16/15`
`2.`
`a) 31/17 + -5/13 + -8/13 – 14/17`
`=(31/17-14/17)+(-5/13+-8/13)`
`=1+(-1)`
`=0`
`b) -5/7 . 2/11 + -5/7 . 9/11 + 5/7`
`=-5/7×(2/11+9/11)+5/7`
`=-5/7×1+5/7`
`=-5/7+5/7`
`=0`