Bài `5`

`10 000 - 47 × 72 - 47 × 28`

`= 10 000 - 47 × ( 72 + 28 )`

`= 100 × 100 - 47 × 100`

`= ( 100 - 47 ) × 100`

`= 53 × 100`

`= 5300`

`3457 - 27 × 48 - 48 × 73 + 6543`

`= ( 3457 + 6543 ) - 48 × ( 27 + 73 )`

`= 10 000 - 48 × 100`

`= 100 × 100 - 48 × 100`

`= ( 100 - 48 ) × 100`

`= 52 × 100`

`= 5200`

Bài `6`

`326 × 728 + 327 × 272`

`= 237328 + 88944`

`= 326272`

`2008 × 867 + 2009 × 133`

`= 1740936 + 267197`

`= 2008133`

`1235 × 6789 × ( 630 - 315 × 2 )`

`= 1235 × 6789 × ( 630 - 630 )`

`= 1235 × 6789 × 0`

`= 0`

`( m : 1 - m × 1 ) : ( m × 2008 + m × 2008 )`

`= ( m - m ) : ( m × 2008 + m × 2008 )`

`= 0 : ( m × 2008 + m × 2008 )`

`= 0`

`#dtkc`

`5.`

`10000 - 47 xx 72 - 47 xx 28`

`= 10000 - 3384 - 1316`

`= 6616 - 1316`

`= 5300`

`3457 - 27 xx 48 - 48 xx 73 + 6543`

`= (3457 + 6543) - (27 xx 48) - (48 xx 73)`

`= 10000 - 1296 - 3504`

`= 8704 - 3504`

`= 5200`

`6.`

`326 xx 728 + 327 xx 272`

`= 326 x 728 + 326 xx 272 + 272`

`= 326 x (728 + 272 ) + 272`

`= 326 x 1000 + 272`

`= 326000 + 272`

`=326272`

`2008 xx 867 + 2009 xx 133`

`= 2008 xx 867 + (2008+1) xx 133 + 133`

`= 2008 xx 867 + 2008 xx 133 + 1 xx 133`

`= 2008 xx ( 867 + 133) + 133`

`= 2008 xx 1000 + 133`

`= 2008000 + 133`

`= 2008133`

`1235 xx 6789 xx (630 - 315 xx 2)`

`= 1235 xx 6789 xx (630 - 630)`

`= 1235 xx 6789 xx 0`

`= 8384415 xx 0`

`= 0`

`(m : 1 - m xx 1) : (m xx 2008 + m + 2008)`

`= m : 1 - m xx 1 : m xx 2008 + m + 2008`

`= (m - m):(m xx 2008 + m + 2008)`

`= 0 : (m xx 2008 + m + 2008)`

`=0`