zadanie 1
[tex] - 1 \frac{2}{5} \times 1 \frac{7}{8} = - \frac{7}{5} \times \frac{15}{8} = - \frac{21}{8} = - 2 \frac{5}{8} [/tex]
[tex]( - 7 \frac{4}{5} ) \div ( - 3 \frac{1}{4} ) = ( - \frac{39}{5} ) \times ( - \frac{4}{13} ) = \frac{12}{5} = 2 \frac{2}{5} [/tex]
[tex]( - 1.6) \times ( - 5.04) = 8.064[/tex]
[tex]0.063 \div ( - 0.7) = - 0.9[/tex]
zadanie 2
[tex]81 - 45 \div (48 - 39) = 81 - 45 \div 9 = 81 - 5 = 76[/tex]
[tex](29 - ( - {2)}^{3} - 6) \times ( - {3)}^{2} = ( 29 - ( - 8) - 6) \times9 = (29 + 8 - 6) \times 9 = 31 \times 9 = 279[/tex]
zadanie 3
[tex]a = 475.3 \\ b = 901.785 \\ c = 2000[/tex]