Đáp án + Giải thích các bước giải:
`a,`
`1/2+ (-2)/3 + 1/6 + 1/7`
`=(1/2 + (-2)/3 + 1/6) + 1/7`
`=(3/6 + (-4)/6 + 1/6) + 1/7`
`= 0 + 1/7`
`=1/7`
`b,`
`1/2 + 1/5 + 1/10 = 5/10 + 2/10 + 1/10 = (5+2+1)/10 = 8/10 = 4/5`
`c,`
`1/2 + (-3)/5 + 1/10 + 2/5`
`= 5/10 + (-6)/10+ 1/10 + 4/10`
`= 4/10 = 2/5`
`d,`
`1/2 +2/3 + 3/4 + 4/5 + 5/6`
`=(1/2 + 2/3 + 4/5 + 5/6) + 3/4`
`=(15/30 + 20/30 + 24/30 + 25/30) + 3/4`
`= 14/5 + 3/4`
`= 56/20 + 15/20`
`=71/20`
`e,`
`1/2 + 1/3 + 1/4 + 1/5 +1/6`
`= (1/2 + 1/3 + 1/4 + 1/6) + 1/5`
`= (6/12 + 4/12 + 3/12 + 2/12) + 1/5`
`= 5/4 + 1/5`
`= 25/20 + 4/20`
`=29/20`