1.Tính nhanh a.10000-47x72-47x28 b.3457-27x48-48x73+6543 2.Tính nhanh a.326x728+327x272 b.2008x867+2009x133 c.1235x6789x(630-315x2) d.(m:1-mx1):(mx2008+m+2008

Đáp án:

↓↓

Giải thích các bước giải:

`1)`

`a)`

`10000-(47×72+47×28)`

`= 10000-[47×(72+28)]`
`= 10000-[47×100]`
`=10000-4700`

`= 5300`

`b)`

`3457-27×48-48×73+6543`

`=3457-[48×(27+73)]+6543`

`=3457-[48×100]+6543`

`=3457-4800+6543`

`=(3457+6543)-4800`

`= 10000-4800`

`=5200`

`2)`

`a)`

`326×728+327×272`

`=326×728+(326+1)×272`

`=326×728+326×272+272×1`

`=326×(728+272)+272`

`=326×1000+272`

`=326000+272`

`=326272.`