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 ) \(\frac{13}{15}+\frac{4}{7}-\frac{101}{105}\)
2: \(=\dfrac{59}{10}\cdot\dfrac{2}{3}-\left[\dfrac{7}{3}\cdot\left(4+\dfrac{1}{2}-2\right)\right]\cdot\dfrac{4}{7}\)
\(=\dfrac{59}{15}-\dfrac{4}{3}\cdot\dfrac{5}{2}=\dfrac{59}{15}-\dfrac{10}{3}=\dfrac{59-50}{15}=\dfrac{9}{15}=\dfrac{3}{5}\)
4: \(=254+254\cdot399+399\)
\(=254\cdot400+399\)
\(=101600+399=101999\)
5: \(=638+3900-41=3900+597=4497\)
