1. 计算:
(1) $16.8×\frac{7}{32} +7.6×\frac{7}{16}$；
(2) $10.4×\frac{3}{8} +5.2×\frac{1}{2} + (-\frac{1}{5}×\frac{26}{5})$。

(1) $7$
(2) $5.46$
【解析】原式$=5.2×2×\dfrac{3}{8}+5.2×\dfrac{1}{2}+5.2×(-\dfrac{1}{5})=5.2×(\dfrac{3}{4}+\dfrac{1}{2}-\dfrac{1}{5})=5.2×1\dfrac{1}{20}=5.2×(1+\dfrac{1}{20})=5.2+5.2×\dfrac{1}{20}=5.2+0.26=5.46.$

2. 计算：
(1) $-3.14×35.2 + 6.28×(-23.3) -1.57×36.4$；
(2) $\frac{1}{8} -0.125×(-5) + (-\frac{3}{8})×5 - (-0.625)×(-7)$；
(3) $-0.31×\frac{3}{4} -3.1×0.025 +15×(-1.75)+15×2\frac{3}{4}$；
(4) $7.535×13 -26×(\frac{7}{9}+\frac{5}{6}-\frac{7}{18})+(-4.035)×13$。

(1) $-314$
【解析】原式$=-3.14×35.2-3.14×2×23.3-3.14×\dfrac{1}{2}×36.4=-3.14×(35.2+46.6+18.2)=-314.$
(2) $-\dfrac{11}{2}$
(3) $14.69$
(4) $13\dfrac{13}{18}$