Question

помогите пожалуйста




вычислите
а) 3+2,1/3
б) 4-2,1/3
в) 5,2/8+7
г) 7,2/4-4

Answer 1

Пошаговое объяснение:

а)

$3 + \frac{2.1}{3} = 3 + \frac{21}{20} = 3 + \frac{7}{10} = \frac{30}{10} + \frac{7}{10} = \frac{30 + 7}{10} = \frac{37}{10} = 3 \frac{7}{10} = 3.7$

б)

$4 - \frac{2.1}{3} = 4 - \frac{21}{30} = 4 - \frac{7}{10} = \frac{40}{10} - \frac{7}{10} = \frac{40 - 7}{10} = \frac{33}{10} = 3 \frac{3}{10} = 3.3$

в)

$\frac{5.2}{8} + 7 = \frac{52}{80} + 7 = \frac{13}{20} + 7 = \frac{13}{20} + \frac{140}{20} = \frac{13 + 140}{20} = \frac{153}{20} = 7 \frac{13}{20} = 7.65$

г)

$\frac{7.2}{4} - 4 = \frac{72}{40} - 4 = \frac{9}{5} - 4 = \frac{9}{5} - \frac{20}{5} = \frac{9 - 20}{5} = - \frac{11}{5} = - 2.2$