Question

помогите пожалуйста решить 25,5+(-34 1/7)+(-1 13/21)=?

Answer 1

$25,5+\Big(-34\dfrac{1}{7}\Big)+\Big(-1\dfrac{13}{21}\Big)=25\dfrac{5}{10}-\Big(34\dfrac{1}{7}+1\dfrac{13}{21}\Big)=\\ \\\\ =25\dfrac{1}{2}-\Big(34\dfrac{3}{21}+1\dfrac{13}{21}\Big)=25\dfrac{1}{2}-35\dfrac{16}{21}=\\ \\ \\ =-\Big(35\dfrac{16}{21}-25\dfrac{1}{2}\Big)=-\Big(35\dfrac{32}{42}-25\dfrac{21}{42}\Big)=\\ \\ \\ =\boldsymbol{-10\dfrac{11}{42}}$