جواب کاردرکلاس صفحه 12 درس 1 ریاضی هشتم (عددهای صحیح و گویا)

\(\begin{array}{l}( - \frac{7}{9}) - ( - \frac{4}{9}) = \frac{{ - 7 + 4}}{9} = - \frac{3}{9} = - \frac{1}{3}\\\\( - \frac{6}{{11}}) + ( + \frac{8}{{11}}) = \frac{{ - 6 + 8}}{{11}} = + \frac{2}{{11}}\\\\( - \frac{6}{{11}}) - ( + \frac{8}{{11}}) = \frac{{ - 6 - 8}}{{11}} = \frac{{14}}{{11}}\\\\ - \frac{6}{{11}} - \frac{8}{{11}} = \frac{{ - 6 - 8}}{{11}} = \frac{{14}}{{11}}\\\\( - \frac{6}{5}) + ( - \frac{{12}}{{25}}) = \frac{{ - 30 - 12}}{{25}} = \frac{{ - 42}}{{25}}\\\\\frac{7}{9} - \frac{4}{9} = \frac{{7 - 4}}{9} = \frac{3}{9} = \frac{1}{3}\\\\( - \frac{4}{7}) - ( - \frac{5}{9}) = \frac{{ - 36 + 35}}{{63}} = - \frac{1}{{63}}\\\\ - \frac{4}{5} + \frac{4}{5} = \frac{{ - 4 + 4}}{5} = \frac{0}{5} = 0\\\\ - \frac{3}{4} - \frac{{15}}{8} = \frac{{ - 6 - 15}}{8} = \frac{{ - 21}}{8}\end{array}\)

\(\begin{array}{l}4 + \frac{3}{7} = \frac{{28}}{7} + \frac{3}{7} = \frac{{28 + 3}}{7} = \frac{{31}}{7}\\\\4 + ( - \frac{3}{7}) = \frac{{28}}{7} + ( - \frac{3}{7}) = \frac{{28 - 3}}{7} = \frac{{25}}{7}\\\\ - 4 + ( - \frac{3}{7}) = \frac{{ - 28}}{7} + ( - \frac{3}{7}) = \frac{{ - 28 - 3}}{7} = \frac{{ - 31}}{7}\\\\ - 4 + \frac{3}{7} = \frac{{ - 28}}{7} + \frac{3}{7} = \frac{{ - 28 + 3}}{7} = \frac{{ - 25}}{7}\\\\4 - \frac{3}{7} = \frac{{28}}{7} - \frac{3}{7} = \frac{{28 - 3}}{7} = \frac{{25}}{7}\\\\ - 4 - \frac{3}{7} = \frac{{ - 28}}{7} - \frac{3}{7} = \frac{{ - 28 - 3}}{7} = \frac{{ - 31}}{7}\end{array}\)

\(\begin{array}{l} - 3\frac{3}{4} = - 3 + ( - \frac{3}{4})\\\\ + 4\frac{1}{3} = + 4 + \frac{1}{3}\end{array}\)