tính nâng cao
1) \(\left(1-\frac{1}{2}\right)x\left(1-\frac{1}{3}\right)x\left(1-\frac{1}{4}\right).............\)
2) \(5\frac{9}{10}:\frac{3}{2}-\left(2\frac{1}{3}x4\frac{1}{2}-2x2\frac{1}{3}\right):\frac{7}{4}\)
3) \(254x399-145\)
4) \(254+399x255\)
5) \(638+780x5-369:9\)
6) \(\left(275+485\right)x16-483:3x4\)
7 ) \(\frac{13}{15}+\frac{4}{7}-\frac{101}{105}\)