Задание 40. Найдите значение выражения: 1) 1 2/5 + 1,7; 2) 1 1/2 + 3,3; 3) 4,5 + 2 1/2; 4) 3,8 − 1 3/5; 5) 5 7/20 − 1,1; 6) 2 3/25 + 4,21; 7) 6,36 − 5 21/50; 8) 5 6/25 − 1,24; 9) 3,05 − 2 1/20; 10) 8,325 − 1 1/8; 11) 3 2/3 + 1,4; 12) 1 4/7 − 1,3; 13) 9,2 − 5 2/3; 14) 1,5 + 7 4/9; 15) 3,3 + 4 5/6.

1. \(1\frac{2}{5}+1,7=1,4+1,7=3,1\).
2. \(1\frac{1}{2}+3,3=1,5+3,3=4,8\).
3. \(4,5+2\frac{1}{2}=4,5+2,5=7\).
4. \(3,8-1\frac{3}{5}=3,8-1,6=2,2\).
5. \(5\frac{7}{20}-1,1=5,35-1,1=4,25\).
6. \(2\frac{3}{25}+4,21=2,12+4,21=6,33\).
7. \(6,36-5\frac{21}{50}=6,36-5,42=0,94\).
8. \(5\frac{6}{25}-1,24=5,24-1,24=4\).
9. \(3,05-2\frac{1}{20}=3,05-2,05=1\).
10. \(8,325-1\frac{1}{8}=8,325-1,125=7,2\).
11. \(3\frac{2}{3}+1,4=3\frac{2}{3}+1\frac{2}{5}=3\frac{10}{15}+1\frac{6}{15}=5\frac{1}{15}\).
12. \(1\frac{4}{7}-1,3=\frac{11}{7}-\frac{13}{10}=\frac{110-91}{70}=\frac{19}{70}\).
13. \(9,2-5\frac{2}{3}=\frac{46}{5}-\frac{17}{3}=\frac{138-85}{15}=\frac{53}{15}=3\frac{8}{15}\).
14. \(1,5+7\frac{4}{9}=\frac{3}{2}+\frac{67}{9}=\frac{27+134}{18}=\frac{161}{18}=8\frac{17}{18}\).
15. \(3,3+4\frac{5}{6}=\frac{33}{10}+\frac{29}{6}=\frac{99+145}{30}=\frac{244}{30}=8\frac{2}{15}\).

Ответ: 1) 3,1; 2) 4,8; 3) 7; 4) 2,2; 5) 4,25; 6) 6,33; 7) 0,94; 8) 4; 9) 1; 10) 7,2; 11) 5 1/15; 12) 19/70; 13) 3 8/15; 14) 8 17/18; 15) 8 2/15.