4. Вычислить: a) -37+(-93) б) 7,421-8,51 в) -476-(-592) г) $$-\frac{7}{8} + (-\frac{3}{12})$$

a) $$-37 + (-93) = -37 - 93 = -(37 + 93) = -130$$ б) $$7,421 - 8,51 = -(8,51 - 7,421) = -1,089$$ в) $$-476 - (-592) = -476 + 592 = 592 - 476 = 116$$ г) $$-\frac{7}{8} + (-\frac{3}{12}) = -\frac{7}{8} - \frac{3}{12} = -\frac{7}{8} - \frac{1}{4} = -\frac{7}{8} - \frac{2}{8} = -\frac{9}{8} = -1\frac{1}{8}$$