0,5×
[tex] (\frac{1}{3} + \frac{1}{4} - \frac{16 - 1}{90} ) \div 2.5 = (\frac{4 + 3}{12} - \frac{15}{90} ) \div \: 2 \times \frac{5}{10} = (\frac{7}{12} - \frac{1}{6} ) \div 2 \times \frac{1}{2} = \frac{5}{12} \div \frac{5}{2} = \frac{5}{12} \times \frac{2}{5} = \frac{1}{6} [/tex]
0,5×1:6=0,5×0,1
=0,5×0,1(6)
=0,8(3)
