a) 112 + (−12)+ (− 487)+ 512

b) 24 - 4^2 : 4.2 + 3

c) 21− 21.[(2.9 + 64 : 32)− 52 ]

2 câu trả lời

`a) 112 + (−12)+ (− 487)+ 512 `

`=112-12+512-487`

`=100+25`

`=125`

`b) 24 - 4^2 : 4.2 + 3`

`=24-16:8+3`

`=24-2+3`

`=22+3`

`=25`

`c) 21− 21.[(2.9 + 64 : 32)− 52 ]`

`=21− 21.[(18 + 2)− 52 ]`

`=21− 21.(20− 52)`

`=21− 21.(-32)`

`=21.[1-(-32)]`

`=21.(1+32)`

`=21.33`

`=693`

 

Đáp án + giải thích :