Tính nhanh a. 76x5+76+76+76x3 b. 1273x250+749x1273+1273 c. 263x76+23x263+263

`a)` `76 × 5 +76 + 76 + 76 × 3`

`= 76 × 5 + 76 × 1 + 76 × 1 + 76 × 3`

`=` `76 × (5 + 1 + 1 + 3)`

`= 76 × 10`

`= 760`

`b)` `1273 × 250 + 749 × 1273 + 1273`

`= 1273 × 250 + 749 × 1273 + 1273 × 1`

`= 1273 × (250 + 749 + 1)`

`= 1273 × 1000`

`= 1273000`

`c)` `263 × 76 + 23 × 263 + 263`

`= 263 × 76 + 23 × 263 + 263 × 1`

`= 263 × (76 + 263 + 1)`

`= 263 × 340`

`= 89420`

$Good_{}$ $luck_{}$