2. Найдите значение выражения: 1) 7+5,31+9+13,49; 2) 62,7+8,31+5,79+0,07; 3) 8,31-(4,29+3,721); 4) (8,21+9,73) - 0,001; 5) 3 1/2 : 5 1/4; 6) 10 2/3 : 5 1/3 : 1/3; 7) (10 2/3 - 5 1/3) : 1/3; 8) 4 1/2 : 5 10/9; 9) 0,7·1,3+5,1:0,17; 10) 3,38-2,24:1,25; 11) (3,38-2,24):1,25; 12) 31,7:63,4-23,4:11,7.

2. Значение выражений:

1. \( 7+5.31+9+13.49 = 34.8 \)


2. \( 62.7+8.31+5.79+0.07 = 76.87 \)


3. \( 8.31-(4.29+3.721) = 8.31 - 8.011 = 0.299 \)


4. \( (8.21+9.73) - 0.001 = 17.94 - 0.001 = 17.939 \)


5. \( 3\frac{1}{2} : 5\frac{1}{4} = \frac{7}{2} : \frac{21}{4} = \frac{7}{2} \cdot \frac{4}{21} = \frac{28}{42} = \frac{2}{3} \)


6. \( 10\frac{2}{3} : 5\frac{1}{3} : \frac{1}{3} = \frac{32}{3} : \frac{16}{3} : \frac{1}{3} = \frac{32}{3} \cdot \frac{3}{16} \cdot 3 = 2 \cdot 3 = 6 \)


7. \( \left(10\frac{2}{3} - 5\frac{1}{3}\right) : \frac{1}{3} = \left(\frac{32}{3} - \frac{16}{3}\right) : \frac{1}{3} = \frac{16}{3} : \frac{1}{3} = \frac{16}{3} \cdot 3 = 16 \)


8. \( 4\frac{1}{2} : 5\frac{10}{9} = \frac{9}{2} : \frac{55}{9} = \frac{9}{2} \cdot \frac{9}{55} = \frac{81}{110} \)


9. \( 0.7 \cdot 1.3 + 5.1 : 0.17 = 0.91 + 30 = 30.91 \)


10. \( 3.38 - 2.24 : 1.25 = 3.38 - 1.792 = 1.588 \)


11. \( (3.38 - 2.24) : 1.25 = 1.14 : 1.25 = 0.912 \)


12. \( 31.7 : 63.4 - 23.4 : 11.7 = 0.5 - 2 = -1.5 \)