`@Kem`
Giải thích các bước giải:
`a, (| -1/4|- | -1/3|)÷(-6)/7`
`= (1/4 - 1/3) × 7(-6)`
`= -1/12 × 7/(-6)`
`= 7/72`
`b, -2 1/4 ÷ (-5)/6 +1/3`
`= (-9)/4 × 6/(-5) + 1/3`
`= 27/10 + 1/3`
`= 91/30`
`c, (3/4 - 0,2)(0,4 - 4/5)`
`= (3/4 - 1/5)(2/5 - 4/5)`
`= 11/20 × (-2)/5`
`= -11/50`
`d, 2/3 - [(-7/4)-(1/2 + 3/8)]`
`= 2/3 - [(-7)/4 - 7/8]`
`= 2/3 - (-21/8)`
`= 79/24`
