1. Найдите значение выражения: 1) (11/24 + 8/16) · 48; 2) (1/7 + 1/4 − 3/14) · 28; 3) (8/26 + 5/39) · 13; 4) (11/45 − 8/75) · 90.

1. \(\left(\frac{11}{24}+\frac{8}{16}\right)\cdot48=\left(\frac{11}{24}+\frac{1}{2}\right)\cdot48=\frac{23}{24}\cdot48=46\).
2. \(\left(\frac17+\frac14-\frac{3}{14}\right)\cdot28=\left(\frac4{28}+\frac7{28}-\frac6{28}\right)\cdot28=\frac5{28}\cdot28=5\).
3. \(\left(\frac8{26}+\frac5{39}\right)\cdot13=\left(\frac4{13}+\frac5{39}\right)\cdot13=\frac{17}{39}\cdot13=\frac{17}{3}=5\frac23\).
4. \(\left(\frac{11}{45}-\frac8{75}\right)\cdot90=\left(\frac{55}{225}-\frac{24}{225}\right)\cdot90=\frac{31}{225}\cdot90=\frac{62}{5}=12\frac25\).

Ответ: 1) 46; 2) 5; 3) \(5\frac23\); 4) \(12\frac25\).