`l) 3232 x 15 - 1515 x 32.`
`= 32 x 101 x 15 - 101 x 15x 32.`

`= 0.`
`o) (175175 x 279 - 279279 x 175) : (101 x 102 x...x 110).`
`= 1001 x (175 x 279 - 279 x 175) : (101 x 102 x...x 110).`
`= (1001 x 0) : (101 x 102 x...x 110) = 0.`
`p) (12+13+....+100) x (7272 x 84 - 8484 x 72).`
`= (12+13+...+100) x 101(72 x 84 - 84 x 72).`
`= (12+13+....+100) x 101 x 0 = 0.`
`r) 57 x 23 + 57 x 44 + 67 x 43.`
`= 57(23+44) + 67 x 43.`
`= 57 x 67 + 67 x 43.`
`= 67 x (57+ 43) = 67 x 100 = 6700.`
`s) 23 x 45 + 23 x 12 + 23 x 24 + 81 x 77.`
`= 23(45 +12 + 24) + 81 x 77.`
`= 23 x 81 + 81 x 77.`
`= 81 (77 + 23).`

`= 81 x 100 = 8100.`
t) 86 x 86 + 14 x 122 + 86 x 75 + 14 x 39
= 86(86 + 75) + 14(122 + 39).`
`= 86 x 161 + 14 x 161.`

`=(86+14)161.`

`= 161 x 100 = 16100.`
`Bài 3:`
`a) 25 x 29 x 4.`

`= (25 x 4) x 29 .`

`= 100 x 29 .`

`= 2900.`
`c) 25 x 3 x 4 x 20.`

`= (25 x 4) x 3 x 20.`

`= 100 x 3 x20.`

`= 60 x 100 = 6000.`